Forum der Vereinigung der Sternfreunde

Erwin wars!

                   Epoch = 2021 July  5.0 TT 
    T = 2021 July 20.21629 TT        Peri. = 186.04331 
    e = 0.4232933                    Node  =  39.02519 2000.0 
    q = 2.1398542 AU                 Incl. =  15.97753 
      a =  3.7104720 AU   n = 0.13789875   P =   7.15 years 

https://minorplanetcenter.net/mpec/K21/K21AE7.html

cbet 4910

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Uwe Pilz, Fachgruppen Kometen und Astrophysik/Algorithmen.
Oft benutzte Instrumente: Swarovski SLC 7x50B, Fujinon 16x70 FMT-SX-2, TMB Apo 105/650, Skywatcher Evostar 120/900 ED, Ninja Dobson 320/1440

Hallo
Endlich habe ich mich in diesem Forum registriert.
Ein frohes neues Jahr wünsche ich allen.
Für mich fängt es gut an, denn dies ist meine 25. Kometen-Wiederentdeckung

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Erwin Schwab
Calar Alto Schmidt (Z84), Taunus Observatorium Frankfurt (B01), ESA Optical Ground Station (J04)
Once upon a time: Starkenburg Sternwarte Heppenheim (611), Tzec Maun Observatories (H10, D25, D96)
www.erwinschwab.de
www.erwinschwab.de/comet

Lieber Erich,

na dann herzlichen Glückwunsch zum Jubiläum! Hervorragend!

Viele Grüße und ein gesundes neues Jahr!

Steffen

Auch von mir Glückwunsch. Da steckt viel Arbeit dahinter. Gruß Michael

Hallo Erwin,

fleißig, fleißig !

habe letzte Nacht versucht, das Teil abzulichten... parallel mit zwei Optiken.
Mal sehen, ob was die kleinen Lichteimer bringen

Viel Erfolg weiterhin !

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Kind regards / Freundliche Grüße
Martin

Hi Gentlemen,

Here is an image of Erwin's recovery from a few weeks ago. It is fairly bright, no evidence of a tail. Martin, when you say you are trying parallel optics, little light buckets, what are you referring to? It sounds like an interesting concept, but maybe I misunderstand.

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Cheers, Mike
Arizona

Hello Mike, and all comethunters,

sorry for beeing that late with my result. This was the faintest comet (for me) imaged on 19th of January this year.
Due to plenty of time remaining, before my next observation target (C/2021 A1) of that night has reached comfortable height, I decided to let 300s exposures run for more than two hours.
Attached is the result of 27 subframes, registered on stars and animated. The comet moves slowly in the upper half of the image, left from the middle.

Mike, what I meant when trying parallel optics, is to expose on both telescopes (a 8"/2.8 and a 12"/4.2), which are fixed side by side on the same mount. I made a VBS (script) which starts the exposure on a Moravian G4 camera controlled by SIPS (Moravians program), as soon as MaximDL starts the 8" exposure. Both exposures can be made with any of the filters at the camera's filter wheel. Somewhat tricky, due to the longer readout time of the G4. But I even found out, how to stop comet tracking, dither and then start comet tracking again by the script. Without this dither, all remaining hot pixels would move together with the comet in all exposures... very nasty.
The "little light buckets" are the two optics, 8" and 12", somewhat usual instruments for us amateurs nowadays. But able to detect very faint objects, when combined with capable sensors and accurately tracking mounts...
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Kind regards / Freundliche Grüße
Martin

Hi Mike and Martin.

These are very good results for that faint comet.
Parallel optics is a nice idea to reduce the background.
I have to propose that to the ESA.
Perhaps I get sponsored a second 0.8m-Schmidt to mount it parallel

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Erwin Schwab
Calar Alto Schmidt (Z84), Taunus Observatorium Frankfurt (B01), ESA Optical Ground Station (J04)
Once upon a time: Starkenburg Sternwarte Heppenheim (611), Tzec Maun Observatories (H10, D25, D96)
www.erwinschwab.de
www.erwinschwab.de/comet

On Feb. 14 I found it at 18m3 with coma and tail. Michael

Hello Michael,

yes, I would confirm the tail and coma.
When I stacked my 27 exposures of 5 minutes on the comet, at least a hint of the tail is clearly visible (comet stack combined with star registered stack; comet in the upper half of the image, left from the middle; same area as animated before).
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Kind regards / Freundliche Grüße
Martin

Hello Martin,

Another nice animation of a very faint comet, the still image isn't bad either! I am impressed with your use of software to start 2 different timed images, stop tracking, dither and then resume tracking for the next couple images. You must have a nice mount for that heavy load, what about your tracking scope?

A few questions about your setup. You use different size scopes with different optics speeds, different cameras different filter wheels. How do you combine what must be 2 different size images with different pixel sizes into a single image for the same time period? Have you adjusted the f ratio seen by each camera to give you the same size and dimensions for both images or do you use software to achieve that result? Do you use different filters for each camera image to maximize different wavelengths to give you a better final result or do you just use filters to eliminate IR and other unwanted wavelengths in your images for such faint comets? I apologize for my lack of knowledge in these questions, but as you stated in another post, we are all trying to learn from each other. If you could post an image of your setup I am sure we would all like to see it.

Erwin, if you do get another 0.8m or maybe just a little 0.4m to do some parallel optics like Martin does, Martin should probably get a little imaging time on that system since he gave you such a good idea.

Gentlemen, a pleasure to read your posts and see your images, have a good day.

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Cheers, Mike
Arizona

Hello Mike,

thank you for kudos. Which I owe to to you all other comet hunters as well
Just a few notes on technical details (a more detailed description I could give for those interested):
The whole observatory and schedule can be fully controlled by CCD Commander, which speaks to MaximDL for exposures (and even cooling of the CCD, an FLI ML-8300) at the 8"/2.8 and starts the vbs script speaking to the Imager window of SIPS for the Moravian G4 exposures. The script looks for exposure start of MaximDL, and within 1 second starts the G4.
The 12"/4.2 has the Moravian G4 attached to it, which has bigger pixels, but due to longer focal length a scale of 1.44"/pixel vs. 1.99"/pixel für the 8". Filters can be set independently. Maximum bandwith is with Luminance for the 8", but at the 12" I preferred a Clear glass (just to avoid refocus) for maximum detection of weak radiation (the sensitivity of the KAF-16803 beyond 700 nm up to 950 nm is still good, so I even invested in a astrodon I'2 filter for a possible "4th band below RGB"). The 8" is piggy back mounted on the 12", which is fixed on a ASA DDM85 (controlled by Autoslew). No tracking or guiding is used.
I process all exposures with PixInsight (PI). The star alignement rescales images to the reference image (preferably of the 12"G4), so slightly increasing the 8" images in pixelcount and resolution (virtually).
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A second 0.8m-Schmidt to mount in parallel to the first is a great idea ... but I think Erwin did kind of a joke when speculating on that. And my idea of parallel exposures "on the same mounted optics" is not that new, somehow common for many years, and realized with different camera controlling software. Due to CCD Commander requirement, I had to stick to SIPS for the G4, however. That was the challenge.
Of course, it would be a great honour to get imaging time on a 0.8m-Schmidt which Erwin can use. But I think he does so as a professional. And the rules of the TAC (Telescope Allocation Committee) must be strictly followed to, not to squander valuable research time
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Kind regards / Freundliche Grüße
Martin