Observation with Discovery 17.5" f/5 - Report of 28th March '09

By admin; Published 05 Oct 2009

BAS member Akarsh, after a wait of 1.5 years, finally received his prestigeous 17.5" f/5 Discovery Dobsonian split-tube scope. It was just 2 days before the Messier Marathon scheduled on 28th! Since this was the scope's first light from a dark place, we obviously decided to keep it an object-marathon rather than confining to only Messiers.

Moving the monster did take some energy. This is no doubt in the top 3 of India's largest and optically finest amateur scopes, and probably the first Discovery around !

Sky condition was very bad in evening with thick haze slimming chances of clearing anytime, but it cleared soon. By night, the skies were all clear with some background illumination and close to ~6 Naked Eye Limiting Magnitude (NELM).

All objects are recollected by us from memory, not one is refered from star charts (except for ocassional position confirming).

There were initially 8-9 people taking their time and observing details taking 30-60 seconds and even more, for each object, then we remained only 3-4 later in the night taking our own time.

Inspite of that we managed to nab details of 45 to 50 galaxies ! Only 1 new comet [sadly missed out on few others due to bad weather in evening :( ] Along were 13 Nebulae (8 planetaries and 5 diffuse), 1 open cluster, and atleast 8 globulars. In all less than 75 objects in one night by a group of people observing each object in detail with the 17.5" scope !!

Here is the detailed description of nearly all the objects (one of the biggest compilations by us) we saw with the 17.5" using 31mm and 11m eyepieces :


1. 22/P Kopff: One of the last objects seen, described first here. I had made a list of couple new comets to be observed with the 8" scope. The evening ones were all clouded out, and now since it was a 17.5" there was no fear of finding anything. I star-hopped to the region from star Pi Sagi to the precise location in Sagittarius as in finder chart. After staring...nothing there!! Akarsh and Me could not see anything, as we were about to give up. But then Akarsh exclaimed as whenever he finds something incredibly faint, and he confirmed it (and his astonishment at finding such a faintie is for limited objects). I looked at the field and this object was so faint that, say with 30 seconds of staring, you could see it for only 5 seconds! It was extremely diffuse with a roundish coma (~5 arcminutes), which got brighter at moments.

Why was it so faint at reported 11th mag (by Juan Jose Gonzalez of Spain), is a surprise to us! Is it only because of the extreme diffuseness? We will check the field in Digitized Sky Survey (DSS). This is a comet which is randomly picked and observed.

2. C/2007 N3 Lulin - This one has faded pretty much in brightness now. I could not see it in Gemini with the 10x50's, try as I may. Knowing only the rough position, I pointed the 17.5" there and scanned around, and stumbled upon it, just as I was about to give up. It had a bright central region with diffuse exteriors. Then, went for the same with the 8" f/8 and there was a stark difference; it was almost not there and very diffuse.


3. M51 + NGC 5195 in CVn - With the 11mm eyepiece, at first glance the galaxy and it's companion appeared wide apart. It were their cores, and on some staring the arms and halo started appearing. Akarsh can elaborate more on this object, since I did not spend much time on this.

4. M101 in UMa - Very large and faint circular ghostly glow. 31mm eyepiece.

5. M104 in Virgo - One of THE HIGHLIGHTS of the night! With the 11mm eyepiece, no words could have described the splendour of the edge-on galaxy with it's thin curved dark lane and central glow. It appeared extremely large and stretched right across the fov. Gave a sense of reality.

6. NGC 4565 in Coma - Extremely long, extended beyond the fov and showed the central dust lane.

7. M81 & M82 in UMa - Both appeared very bright. M81 showed a large but diffuse halo. The thin edge-on M82 appeared interesting with atleast two dark streaks (lanes) perpendicular to the center. Nearby elliptical NGC 3077 appeared condensed.

8. M83 in Hydra, M108 and M109 in UMa - These galaxies did not render as much details as expected for this aperture.

9. Antennae (NGC 4038 & 4039) in Corvus - This is nicknamed 'Valentine's Galaxies' by me, for the obvious heart shape formed by the merger of these two galaxies.

10. M65, M66 and NGC 3628 in Leo - I could feel the 'depth' in the tilted galaxy M66. NGC 3628 exhibited a thin central dust lane.

11. Hickson 44 group - One of the Hickson groups (maybe #44) in Sickle of Leo showed 3 galaxies easily, with no detail. We did not see NGC 3185 beside, since we didnt know it.

12. NGC 2683 in Lynx / Cancer border - This has shown us a warped dust lane in a 12" scope once. This time with the large scope, it appeared elongated, and was not more detailed.

13. M64 in CVn - The 'black eye' of this galaxy seen, which is why it's named so. Just a black smear of light below the central core.

14. NGC 4945 and 4976 in Centaurus - A very diffuse and extremely elongated galaxy. NGC 4976 is a smudge of light in the field. We missed NGC 4945A galaxy in the same field.

15. Centaurus A in Centaurus - Appeared very large with the 11 mm eyepiece. This time the central dust lane separated the two halves of the galaxy quite wide. It appeared going straight, as compared to the warped shape in a 8" scope. Two stars embedded in the galaxy.

16. Markarian's Chain in 'Downtown' Virgo - What a view this gave! After letting your eyes adapt to the incoming photons from this distant galactic cluster, you would go on counting like 6..7..8..9 some of them 10 galaxies. I counted 11 at max. This was because everyone was orienting and looking differently. With M84 and M86, NGC's 4388, 4387, 4402 and 4407 formed the left quarter. 'The Eyes' galaxies NGC 4438 and 4435 with the tiny 4407 were centered. And two small ones NGC 4468 and 4451 were at the right edge.

We decided to stop at it, since we would be 'lost' if we ventured deep inside.

17. M87, M98, M99 and M100 in Virgo - M98 appeared very bright and elongated. M87 was very bright as usual. M99 and M100 details could be elaborated by Akarsh.

18. M95, M96 and M105 in Leo - I counted around 6 galaxies in this region. They were all bright.


19. Omega Centauri in Centaurus - NO WORDS TO DESCRIBE IT WHATSOEVER!! Thousands of stars littered across the fov, each appearing perfectly stationary and gave a sense of mighty awe!! You could even resolve the gaps between each star in the core region with the 11mm!!!

20. M5 in Serpens - With the 31mm eyepiece, it appeared very resolved, and the stars at the edge were less in number and spaced apart.

21. M4 in Scorpius - Appeared very resolved. At the other edge of the field was the companion globular NGC 6144.

22. M80 in Scorpius- Perfect example of a new comet due to it's condensed appearance.

23. NGC 5286 in Centaurus - This one with it's nearby star provided a stark cotrast.

24. M22 in Sagi - Appeared resolved with stars sprikled on the foreground.

25. NGC 6624 in Sagi -Appeared condensed and cometary.


26. M97 (OWL) in UMa- We could sense the Owl's eyes with the 11mm eyepiece. With the 31mm it appeared very bright and condensed.

27. NGC 6543 (CATS EYE) in Draco - Appeared bright and small, condensed. We did not observe the external filaments.

28. NGC 2392 (ESKIMO) in Gemini - WHAT A BEAUTY! One of the best observations with the 11mm eyepiece. We could clearly see the Eskimo's face, surrounding woolly hood and even the central star.

29. NGC 3242 (GHOST OF JUPITER) in Hydra - Very blue and bright with the 11mm eyepiece. Surrounding flowery envelopes also seen.

30. M57 (RING) in Lyra - With the 31mm, it appeared very bright with the central hole clear. With the 11mm eyeiece, we could see a larger version of this, and tried to look into the cetral gray hole, but to no avail for the central star.

31. M27 (DUMBBELL) in Vulpecula - WHAT A BEAUTY! With the 11mm eyepiece, it appeared very huge and bright, and with the OIII filter on, the side wisps were equally as bright. With the 31mm eyepiece, it was no less beautiful. Removal of the filter removed the wisps.

32. NGC 4361 in Corvus - Just a small circular fuzz.

33. Bug Nebula in Scorpius - Just a small horizontal streak of light.


34. M17 in Sagi - Looked like a perfect Swan. Very beautiful and bright.

35. M20 in Sagi - The Trifid (three cutting lanes) was easily visible.

36. M8 in Sagi - We saw this in oncoming twilight and it was visible nebulous.

37. M16 in Serpens - We saw this in oncoming twilight and it was visible nebulous.

38. M42 + M43 in Orion - Very detailed and showed some dust lanes cutting through. Trapezium with 4 stars visible. Could not observe much since evening haze obstructed, and it set behind a tree.


39. M7 in Scorpius - This is the only open I remember we focussed at, since we were up with the above list. Appeared just as with any other aperture.


This completes the list I remember off-hand, with detailed descriptions whereever possible, and jists for most others. Akarsh and others are requested to add additional details as comments.