You are not logged in. [Login] Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar

Astrophotography and Sketching >> CCD Imaging & Processing Previous   Index   Next   Threaded

Pages: 1 buckeyestargazer Pooh-Bah Reged: 01/12/08 Loc: IN, USA NGC772 at f/11       #5528212 - 11/19/12 03:34 PM Edit   Reply   Quote Quick Reply   It's been a long time since I tried to image a galaxy, and as usual someone else beat me to the punch with a very fine image of this interesting galaxy (see this thread: unusual: NGC772 in Aries) Here's my attempt: NGC772 This image was made using a "synthetic luminance" created from the best LUM, R, G, and B sub exposures. I took the best 50% of subs in each channel and combined them to create a rather smooth and detailed synthetic luminance. I was rather pleased with the result of this synth LUM, so much so that I will probably use this method going forward. Also, this is my second image using a Tak TOA 1.6x extender, pushing my APM115 f/7 refractor to f/11. The extender narrows the field of view, the tradeoff being that longer exposures are necessary. I started with 10min exposures but soon realized that 20min exposures would be better. I'm still not 100% convinced that using an extender like this is all that great for AP, but I think the result of NGC772 is pretty good considering this is from a 4.5" 115mm refractor and not a larger SCT with more aperture and focal length. What are your thoughts? Post Extras:       sergeC14 member Reged: 05/12/10 Loc: Frech Alps, france Re: NGC772 at f/11 [Re: buckeyestargazer]       #5528603 - 11/19/12 07:12 PM Edit   Reply   Quote Quick Reply   Well Joel, That's a very good effort at a very nice galaxy! How many subs did you use? All the details are there, but I think it could benefit from more exposures. I used 5 hours on mine. It's funny that you took yours in America, and I did mine in the French Alps, a big ocean apart. How cool is that? Rgds Serge Post Extras:       buckeyestargazer Pooh-Bah Reged: 01/12/08 Loc: IN, USA Re: NGC772 at f/11 [Re: sergeC14]       #5528634 - 11/19/12 07:25 PM Edit   Reply   Quote Quick Reply   Serge, This is nearly 12 hours already! I don't think any more time will help. I think this is the best I could get with my skies and 4.5" aperture. Post Extras:       sergeC14 member Reged: 05/12/10 Loc: Frech Alps, france Re: NGC772 at f/11 [Re: buckeyestargazer]       #5529314 - 11/20/12 02:21 AM Edit   Reply   Quote Quick Reply   oops, I hadn't realized that! You are right, diameter and sky transparency and light pollution will definetely make the difference! Rgds Post Extras:       freestar8n Carpal Tunnel Reged: 10/12/07 Re: NGC772 at f/11 [Re: buckeyestargazer]       #5529344 - 11/20/12 03:46 AM Edit   Reply   Quote Quick Reply   Hi- I think this is a great thing to try and it worked well. I rarely see refractor imaging at f/11, or with OAG - and this is both. It looks like you have a lot more detail than you would have had without the extender and without OAG, so you are getting the benefit of both. At the same time, in terms of deep enough sub-exposures you do need to go longer at higher f/ratio - and that effect is very real. But that is a tiny little thing and it looks like it benefitted from the added effort. Nice thing to try - and looks good to me. Frank Post Extras:       kfir Simon Vendor-PowerNewt Reged: 09/21/10 Re: NGC772 at f/11 [Re: freestar8n]       #5529401 - 11/20/12 05:30 AM Edit   Reply   Quote Quick Reply   You managed to pull out great details with lovely colors - well done! Kfir Post Extras:       zoran professor emeritus Reged: 06/09/06 Loc: Zagreb, Croatia Re: NGC772 at f/11 [Re: kfir Simon]       #5529492 - 11/20/12 07:11 AM Edit   Reply   Quote Quick Reply   Very nice image, sharp and colorful! At f11 it is a real achievement! Regards, Zoran Post Extras:       buckeyestargazer Pooh-Bah Reged: 01/12/08 Loc: IN, USA Re: NGC772 at f/11 [Re: freestar8n]       #5529578 - 11/20/12 08:25 AM Edit   Reply   Quote Quick Reply   Quote: Hi- I think this is a great thing to try and it worked well. I rarely see refractor imaging at f/11, or with OAG - and this is both. It looks like you have a lot more detail than you would have had without the extender and without OAG, so you are getting the benefit of both. At the same time, in terms of deep enough sub-exposures you do need to go longer at higher f/ratio - and that effect is very real. But that is a tiny little thing and it looks like it benefitted from the added effort. Nice thing to try - and looks good to me. Frank Thanks everyone! Frank, you've encouraged me to keep trying at this. Perhaps I should next try to image NGC772 without the extender and compare the results. An object of this size (7') is almost the smallest sized object I can attempt with my setup. Even in this image, I cropped out about 25%. So those tiny planetaries and smaller galaxies are still out of reach. But I think the extender does open the door to some mid-size galaxies that I might not otherwise attempt. Post Extras:       rigel123 Postmaster Reged: 06/29/09 Loc: SW Ohio Re: NGC772 at f/11 [Re: buckeyestargazer]       #5530278 - 11/20/12 02:16 PM Edit   Reply   Quote Quick Reply   That looks great Joel, nice colors! Post Extras:       J.P.M Post Laureate Reged: 11/14/06 Loc: 65"01'N25"47'E Re: NGC772 at f/11 [Re: rigel123]       #5530478 - 11/20/12 03:46 PM Edit   Reply   Quote Quick Reply   Love the "spacey" feel. Post Extras:       freestar8n Carpal Tunnel Reged: 10/12/07 Re: NGC772 at f/11 [Re: buckeyestargazer]       #5530603 - 11/20/12 04:43 PM Edit   Reply   Quote Quick Reply   Quote: Perhaps I should next try to image NGC772 without the extender and compare the results. I would be very interested in such a result. I wouldn't want to sway you from imaging something else on a good night, but I'm personally interested in how much more detail you get with the extender. I assume the OAG is also looking through the extender (I assume?), and I'm a believer that longer focal length helps both guiding and imaging - as long as the guiding is good and the seeing good enough to show the benefit. Frank Post Extras:       bill w Postmaster Reged: 03/26/05 Loc: southern california Re: NGC772 at f/11 [Re: freestar8n]       #5532609 - 11/21/12 04:33 PM Edit   Reply   Quote Quick Reply   nice job joel Post Extras:       Pages: 1

Previous   Index   Next   Threaded

Extra information 11 registered and 24 anonymous users are browsing this forum. Moderator:  Oldfield, bilgebay  Print Thread Forum Permissions       You cannot start new topics       You cannot reply to topics       HTML is disabled       UBBCode is enabled Thread views: 375 Jump to *Announcements and News* -----   Cloudy Nights Announcements   Discussion of CN Articles, Reviews, and Reports   Celestial Events*General Astronomy* -----   Beginners Forum   General Observing and Astronomy   Outreach   Light Pollution*Equipment Discussions* -----   ATM, Optics and DIY Forum   Binoculars   Binoviewers   Cats & Casses   Classic Telescopes   Equipment   Eyepieces   Mounts   Observatories   Reflectors   Refractors    Video and Electronically Assisted Astronomy*Astrophotography and Sketching* -----   Beginning and Intermediate Imaging   Film Astrophotography   DSLR & Digital Camera Astro Imaging & Processing   CCD Imaging & Processing   Solar System Imaging & Processing   Sketching   Astro Imaging/Sketching Contest *Observing* -----   NEO   Planetary and Solar System Observing   Lunar Observing   Deep Sky Observing   Double Star Observing   Solar   Variable Star Observing and Radio Astronomy*Telescope Specific Forums* -----   Celestron NexStar    NexStar GPS / CPC Telescopes   Questar Forum   Meade ACF/RCX / LX / GPS    Meade ETX*Speciality Forums* -----   Arizona Science and Astronomy Expo   NEAF (Northeast Astronomy Forum) and NEAIC (Northeast Astro Imaging Conference)   AstroArt   Astronomy Clubs and Star Parties   Astronomy Software & Computers   AstroWebsites   Science! Astronomy & Space Exploration, and Others   Space Rocks   Stellar Media*Swap and Shop* -----   Shop and Swap Audio Components*CN Feedback and Vendor Announcements* -----   Vendor and Group Announcements*International Year of Astronomy 2009 - Forums are now closed.* -----   IYA Archive Info

CN Forums Home