Archive for April 2018

Messier 81 and M82: Galaxy Pair – Ursa Major – April 2018 – Observer’s Challenge Report #110

April 29, 2018

April 2018 Observer’s Challenge Report:  APRIL 2018 OBSERVERS CHALLENGE – M-081-82-1

Messier 81 (NGC 3031) Galaxy in Ursa:   10-inch f/4.5 reflector.  Sketch magnification; 12 mm eyepiece 95x.  

80 mm refractor at 33x, M81 is large, bright, mostly round with a brighter nucleus, and is nicely framed with companion galaxy M82.   

10-inch reflector at 95x, M81 is bright, large, well concentrated, elongated, but subtle, NE-SW.  Very bright nucleus, almost stellar.  Only on nights of excellent seeing and transparency can the spiral arms be seen from my moderately light polluted backyard.   RI   

Rogers M-081 Inverted

 

Messier 82 (NGC 3034) Galaxy in Ursa Major:  10-inch f/4.5 reflector @ 191x magnification.  Eyepiece:  12 mm plus 2.8x Barlow 

80 mm f/5 refractor:  Surprisingly bright, elongated with a lens shape, smooth texture at low magnification.  When increasing the magnification to 75x, the galaxy becomes very uneven and mottled, with two brighter knots toward the middle, and an outer elongated halo.  This galaxy is much fainter than it’s companion, Messier 81.

10-inch reflector:  Bright, very elongated, dark band in the central region is almost separating the galaxy, and is very easy at 114x, but really comes out at 200x.  At the higher magnification the galaxy becomes very mottled, and with a faint surrounding halo extending the length of the galaxy.  The NE and SW edges or tips of the halo are smooth.   RI   

Rogers M-082 Inverted

Notes from April 1978:  

It wasn’t until the mid-70’s when I acquired my very own telescope, a 4 1/4-inch Edmund Scientific reflector, a Palomar Jr. which was not my first choice, but the best my budget would allow.  

I’ll never forget one special night using this telescope. I was attempting to locate M81 and M82, two of the most beautiful galaxies in the heavens. By this time, the fabulous skies of my early years were gone. I’d moved to an area packed with houses and street lights, and the light pollution was very severe in my back yard.

Attempting to find even the brightest deep-sky objects under these conditions proved to be difficult.  I had tried on many occasions to find M81 and M82, without success.  I wanted to see this galaxy pair, which appeared so striking and beautiful in the magazines.

One night, while observing, time was running out.  It was already after 11:00 PM, and needed to get up early the next morning.  I used my hands in an attempt to block the ambient light from entering my eyepiece, and then it happened: A small, faint fuzzy object entered my telescope view.  I then nudged the scope slightly and then another…..finally M81 and M82.  What a beautiful sight!  I savored the view for the longest time and to this day and I can still feel that excitement.  RI 

Below:  Wide field image of M81/M82 and also NGC 3077, by Dr. James Dire at Wildwood Pines Observatory in Earl, North Carolina:

Image 1

 

 

Antares – Alpha Scorpii – It Can Be Difficult To See The Companion, But Easy When Using A UHC Nebula Filter?

April 24, 2018

Antares:  Magnitudes 1.0/5.4 with a separation of 3.2 arc seconds.  

Notes from July 6th, 7th and 13th 1995:  “10-inch reflector; seeing good.  Tried all eyepiece combinations, but could not see the companion.”   

The glare of the bright primary makes this a difficult pair to split, despite good seeing and a well-collimated 10-inch reflector.

July 1995:  While browsing through some back issues of Sky & Telescope, I found an interesting article by Walter Scott Houston (December 1991 issue, p. 685) concerning the use of a UHC nebula filter to show the companion to Antares, as reported by Richard Miller.  

The article stated that the companion was barely visible using a 10-inch reflector at 230x, but that the filter showed the fainter star easily through a 6-inch at 96x.  

“The filtered view through the 10-inch showed two crisp disk with a band of sky between them.  Furthermore, the filter’s selective transmission causes the pair to appear deep red and apple green.”

Would the UHC filter work for me?  

I set out to try this for myself on the night of July 14th 1995.  All of my previous efforts to view the companion to Antares through my 10-inch reflector had failed.  

However, when I used an Orion Ultrablock nebula filter with my 10-inch at 240x, there it was…..the companion was clearly visible.  

Because of the filter….both stars appeared greenish, but were only visible for a short period.  The conditions, which were good for double stars earlier, quickly deteriorated as a hot breeze began to stir.      

Roger Ivester  

 

Polaris – Double Star – Seeing the Companion With a Small Telescope, Maybe Even As Small As 30 mm’s?

April 15, 2018

Polaris has never gained much attention as a double star.  However, If you’ve had an interest in double stars, but never seemed to get started, Polaris would be a great double to start with, especially with a smaller telescope.  

For this project, lets call a small telescope, anything 80 mm’s or less. 

Information from the “Cambridge Double Star Atlas” by James Mullaney and Wil Tirion, as a reference:

Polaris has a magnitude of 2.1 and the secondary or companion at a much fainter 9.0 magnitude with a wide separation of 19 arc seconds.  The extreme difference in magnitudes can make this double more difficult to separate than you might think, especially if seeing is less than good. 

Sometimes I check this star frequently, when setting up, to gauge seeing.  I  have some notes and sketches from years past, and current using some small telescopes.   

July 1996:  4-inch Meade Schmidt-Cassegrain f/10, model 2045d:  Seeing only fair, companion was not visible.  Roger Ivester – North Carolina 

September 1996:  4-inch Meade Schmidt-Cassegrain f/10, model 2045d: Seeing very good, could easily see the companion at 50x.  RI

September 1996:  5-inch C5 Schmidt-Cassegrain, white-tube with the single arm fork. Made in USA.  Easy, beautiful and clean.  RI

February 1997:  4-inch Meade Schmidt-Cassegrain f/10, model 2045d: Seeing only fair.  The companion was visible only intermittently.  RI 

October 1997:  90 mm Meade ETX Astro-Scope, Maksutov-Cassegrain: Seeing was good and the companion was very easy at 52x.  RI 

December 1998:  102 mm Vixen/Orion f/9.8 achromatic refractor: Very easy to see the companion at all magnifications.  Roger Ivester 

I was unsuccessful during the week of April 8th 2018, using my latest small economy Orion CT80 f/5 refractor.  Seeing was only fair, so I’ll try it again in the next night or so.   Roger Ivester 

April 17th 2018:  102 mm Vixen/Orion f/9.8 achromatic refractor:  Seeing was very poor, could still see the companion, but only intermittently, using full 102 mm aperture.  Did not even attempt with an effective aperture of 60 mm’s.  RI 

Mike McCabe of Massachusetts was able to see the companion last summer on a night of excellent seeing, using a vintage and classic Sears 60 mm f/15 refractor.   

Observing notes by Mike McCabe as following, for the night of April 18th 2018:  It’s been great getting to know, Mike, who is a very experienced and skilled observer. 

Notes from Mike McCabe:  

Well, you really got my interest with your lobbying everyone to try and go see the secondary to Polaris with a small scope.  I got lucky here last night – totally unexpected it was – with a clear and stable sky sometime around 9pm local time. 

At first I turned my interest to the 10% waxing crescent moon, and I brought out my SV80ED to have a quick look.  It was spectacular, with incredible earthshine on the moon and a dark, clear sky around it.  There were nearly as many stars in the view as you’d see during an eclipse!  I watched the moon occult a star (don’t know which one) and then toured the Haydes, the Pleiades and then Polaris.  The 80mm brought out the secondary with no trouble.

I decided to bring out the Sears 60mm f/15.  That was a good decision!  I put Polaris in the eyepiece and ramped the power up to 112x.  In short order I had the secondary in view at an ~5:00 position in the field of view.   

I’ve assembled a 0.965 eyepiece kit, which includes a 40mm, 25mm, 15mm, 12mm, 10mm, 8mm and a 2x Barlow.  I tried many eyepiece combinations, and must’ve looked at Polaris for an hour, and I could see the secondary from 60x all the way up to 180x.  The best magnification occurred at 90x, with 75x being a close second.  At 112x and higher it was still there, but more intermittently.

After last night I’m going with “it’s not only possible to see the secondary to Polaris in a 60 mm telescope, but very, very doable”.  

I have another 60 mm f/15 OTA (a 1980’s era Celestron FirstScope) which I am currently setting up.  I’m wanting to complete the Astronomical League’s Double Star list to receive my certificate which I started working on quite a few years ago, but have never finished.     Mike McCabe – Massachusetts 

April 19th 2018:  102 mm Orion/Vixen f/9.8 achromatic refractor with an effective aperture of 60 mm’s.  Seeing excellent: 12.5 mm eyepiece plus 2.8x Barlow for a magnification of 80x.  The companion was clearly visible as a tiny bluish dot.  Roger Ivester – North Carolina 

April 19th 2018:  Orion 80 mm (CT80) f/5 achromatic refractor.  Seeing excellent: 12.5 mm eyepiece plus 2.8x University Optics Klee Barlow for a magnification of 90x.  The companion was visible as a tiny bluish dot.  Very similar to the view using the 102 mm reduced to 60 mm’s.  A beautiful sight in both telescopes.   Roger Ivester  

When observing with my CT80 or 102 mm refractor, I always use a 1.25-inch correct image diagonal.  For me it’s essential when sketching a deep-sky object, to have the correct orientation in the eyepiece field-of-view.  

April 20th 2018:  Orion 80 mm (CT80) f/5 achromatic refractor.  Similar conditions to my observation on the 19th. Using the same eyepiece combinations (90x) and was able to easily see the companion as a tiny bluish dot.  RI 

April 23rd, 2018:  What?  Observations seeing the companion with far smaller apertures than 60 mm’s:

Polaris and companion:

“Celestial Objects For Common Telescopes” By Rev. T.W. Webb – 1859 

“Spec. Bin., and slightly var. D., 9 blsh. as I see it.  Common test, but only suited for small apertures, being easy with anything much exceeding 2 in.  D. has proposed it as a general standard, finding that 80 on 2-in. will show it if the eye and telescope are good; he has glimpsed it with 1 3/10-in. achr.  Dawson has glimpsed it with 1-inch.  T. T. Smith sees it with 1 1/4-in. refl.  In Dorpat achr. it has been perceived by day.  De. gives it 8.4 m.”

1 3/10-inch = 33 mm’s 

1 1/4-inch = 32 mm’s 

1-inch = 25.4 mm’s 

Just when I thought seeing the companion with 60’s mm’s was really something, I received a telephone call yesterday PM (April 23rd 2018) from ATMoB member and friend, Richard Nugent.  

Richard was using a 10-inch reflector with a 40 mm off-axis stop-down mask, and was successful in seeing the companion.  

The following is a photo of my 102 mm refractor with a stop-down mask for an effective aperture of 60 mm’s.  I’m currently making a 30 mm and 40 mm mask for the next clear night with good seeing. 

IMG_0023

Orion (CT80) 80 mm f/5 refractor.  Yes….I can see the companion to Polaris with this small short focal length achromatic refractor!   My son bought this telescope for my birthday, and it will always be a prized possession of mine….

IMG_2497

35 mm f/29 refractor telescope:   
Now for that excellent night of seeing, and a 12 mm eyepiece for the perfect magnification of 83x.  I’ll not be using a diagonal, but looking straight thru the telescope with only an eyepiece and a 1.5-inch extender tube to allow for proper focus.  The diagonal is not necessary, and would only be extra glass to view through…..with no purpose. 

357125662_6_1

IMG_0037

May 2, 2018:  This was the third night in my attempt to see the companion using  an effective 35 mm aperture.  Seeing was only fair, and could not see the companion, nor with a larger 45 mm effective aperture.

I’m thinking of a new plan, which is to make a 45 mm and a 35 mm off-axis aperture mask for my 6-inch reflector, and my 10-inch reflector.  I’ve always had excellent results on difficult doubles using my 10-inch with a stop-down mask.  I’ll continue to make entry posts.  Roger Ivester 

 

April 2nd 2018:  Report by Richard Nugent 

    Roger, thanks for inspiring me to observe Polaris and it’s faint companion star, Polaris B. As I mentioned I’ve observed the pair more these past few weeks than in total over the last five decades! I’m glad I did. Here’s my report to date…

    The challenge was to see if one could detect B using small aperture refractors. While I do own one or two refractors, it was easier for me to make an aperture mask to fit over the front of my 10-inch f/4.7 reflector. The mask offers  unobstructed apertures of 90, 80, 70, and 60mm. A rotating cover allows me to change apertures very quickly and, with no obstructions, I get refractor-like images! When was the last time you saw Airy disks with your reflector? I thought so. As a bonus, the change to longer focal ratios produces exit pupils much smaller than the average eye’s entrance pupil. The eyepieces I chose to use were a 26mm Plössl (46x), a 16mm Nagler (75x), a 12mm Nagler (100x), and a 7mm Nagler (170x).
    

     The seeing was a little better than average, perhaps 6/10 but with the aperture masks the seeing improved to about 9/10!  Polaris B is about 19” away from Polaris so separation is not the issue. Seeing the B star only requires an aperture with a faint enough limiting magnitude. Of course, on any given night, a telescope’s limiting magnitude is dependent on many factors that are difficult to quantify. Limiting magnitude tables seem, to me, to be overly optimistic!
      I had no trouble detecting the companion with the full aperture. I expected to have to ferret the star out of Polaris’s glare but the B star is about 19” away and was very easy to see. And, after the view through the 10-inch I knew exactly where to look for it. I attached the mask and began with the 90mm aperture. The star was visible at all magnifications. Ditto using the 80 and 70mm apertures.
    

     On to the 60mm. At 170x the star was very difficult and I suspected the magnification was a bit much for the sky conditions. Remember, 50x per inch, right? At the lower magnifications the B star was easy. It really helped that I knew where the star was. Honestly, if I hadn’t known where to look I’d would likely have missed it.
    

     Next,  I took a look at the moon. I grabbed my Meade QX 30mm Wide Angle eyepiece (40x, 1.5mm exit pupil, and a 1.75 ° true field of view) and…the view was nothing short of spectacular! The image was tack sharp, steady as a rock, and pleasingly bright. In all my years of observing I’ve never seen the moon look like that through any 60mm refractor I’d ever looked through! And then it struck me. I was using quality eyepieces filled with modern glass and superior coatings. I think if owners of small refractors invested in better eyepieces they’d use their scope more often and thoroughly enjoy each session. Even 0.965” refractors can be fitted with an adapter to allow for 1.25” eyepieces. The only concern might be some vignetting with wide field eyepieces.
     The next day I let Roger Ivester know of my success with Polaris B and he wondered out loud — how small of an aperture might we go and still see the B star. That night was clear so I constructed 50mm and 40mm masks. I used the same eyepieces used the night before in addition to a Tele Vue 32mm Plössl. Also, I wanted to try some old school, 0.965” eyepieces. I have a box of “junk” and there I found a few eyepieces to try. None of these were branded but they are likely Tasco, 0.965”: SR5mm, H12.5mm, and H25mm. I also have a Meade 25mm modified achromatic. Huygens and Symmetrical Ramsden eyepieces are two lens systems designed in the 17th and 18th centuries, respectively. A Modified Achromat eyepiece is a 3-lens design similar to a Kellner eyepiece.
   

     I first tried the 0.965” eyepieces with the 60 mm mask. I had to hand-hold the eyepieces (my adapter wouldn’t fit into the focuser. Hmmm.) I could not see the B star with any of the Tasco eyepieces but I could just glimpse it with the Meade. I really tried to see the star with the Tasco eyepieces but I was not surprised by their performance.
     With the 50mm mask in place I could not see B at 170x although the Airy disk of Polaris was very impressive! A bit later, upon close examination, I could see the companion only with averted vision and during moments of steady seeing. The star was easily visible in the other modern eyepieces. I attached the 40mm mask and could see the star with the 32mm and 16mm eyepieces! It was not visible at all with the 7mm eyepiece.
   

   Two nights later I located Polaris 15 minutes before sunset using the full aperture of my 10-inch scope but I could see no trace of the companion.  Later, despite the very bright moon in the sky, I tried a 30 mm mask. I could see the companion faintly using the 60mm mask but the star vanished when I flipped the 30mm mask in place. I went no further that night.
      The bottom line: When using modern eyepieces a small aperture refractor can be a fine instrument. Upgrade your eyepieces and give it a try!  Richard Nugent – Massachusetts 

 

May 6th 2018:  Report by Roger Ivester

Last night, seeing was excellent, and a 6-inch f/6 reflector, with an off-axis 45 mm effective aperture, could glimpse the companion, but with extreme difficulty.  This required over more than an hour, using good breathing techniques, as it’s easy to “involuntarily” hold your breath, when attempting a close or faint companion, such as Polaris B.  I also used an eyepatch over my non-observing eye, to relax my face.  

It’s my opinion, it’s “next to impossible” to observe a difficult double (test) such as this while standing, neither have I been been able to observe any type of deep-sky object while standing.  

I’m not planning to attempt anything smaller than 45 mm’s.  Richard Nugent of Massachusetts has the modern day record, or at least the only amateur I know personally, who has seen the companion with 40 mm’s.  This was using a 10-inch reflector with a 40 mm off-axis stop-down mask.     Roger Ivester – North Carolina 

Orion CT80 Refractor Review

April 4, 2018

Telescope:  Orion 80 mm compact f/5 achromatic refractor.  Item #09202 

IMG_2497

I’ve been wanting a small economical refractor for visual observing only.  A telescope that could be used for those quick observing sessions when time is limited, and also for terrestrial viewing.  A telescope which could easily be taken on trips, but taking up very little space. 

A Surprise!

My son surprised me with an Orion model CT80 f/5 refractor as a gift.

This telescope is sold as an optical tube assembly, without accessories from Orion Telescopes and Binoculars.  However, no problem.  I have extra finders, an equatorial mount, an extra or two diagonals, and plenty of eyepieces and a tripod for terrestrial viewing.

I was not wanting an expensive 70-80 mm apochromat, but an achromat, that was light and easy to take outside and bring back in.  

The dovetail mount fits perfectly to my Vixen/Orion GP mount.  I purchased a three pound counterweight about ten years ago, apparently just waiting for this scope.   It balances the telescope perfectly. 

A much smaller and lighter duty equatorial mount would be sufficient for the CT80, but the GP makes for a rock steady mount for sure.  A good quality tripod could also suffice for either astro or terrestrial viewing. 

When taking the scope outside, I carried both the telescope and mount with ease.  With the tripod legs folded together, I was able to hold everything with one arm, while opening and closing the door.  Everything was working perfect so far, but how would this little refractor perform on the night sky?

First Light:

My first target was the beautiful double star, Castor, in Gemini.  I started with 33x, but this was not enough magnification.  With the employ of a 2.8x Barlow, giving a magnification of 93x, I was amazed.  Castor was cleanly separated, with beautiful airy disc rings surrounding both components.  

My next object was the Trapezium in Orion.  The four primary components were crisp and clean even at 33x.  When increasing the magnification to 93x, it was a beautiful sight indeed.  

The Orion Nebula appeared very bright with excellent contrast.  I was actually surprised at this view, which would only be possible with a telescope having excellent anti-reflective coatings.   

What about galaxies?  

M81 and M82, located in Ursa Major, have always been two of my favorite galaxies.  They were very easy to locate, both fitting nicely within the large 1.8º field of view at a 33x magnification.  Beautiful!  This took me back forty years, when I first observed this galaxy pair with a 4.25-inch Edmund Equatorial reflector. 

I’d been outside for almost an hour which was my time allowance for this night.  

Never would I take out my 10-inch equatorially mounted reflector, or my 102 mm refractor or 6-inch reflector, both also with EQ mounts for less than an hour.  This telescope had already proved its value and convenience as being light and compact, and also providing excellent views of brighter deep-sky objects.  

The scope passed all test with flying colors.  I’m very impressed with my new telescope.   

Final:  A portable and versatile telescope for an excellent price. 

https://www.telescope.com/Orion/Telescopes/Beginner-Telescopes/Orion-CT80-80mm-Compact-Refractor-Telescope-Optical-Tube/rc/2160/pc/-1/c/1/sc/21/p/118189.uts

Roger Ivester