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Hello all,
I would like some advice on imaging M104 remotely. I only have 30mins max per night total access - this includes slewing, focusing and filter changes, and perhaps calibration files (not all nights obviously possible due to demand at the observatory).
How much exposure time would be needed to build up a reasonable image from a 17 inch Planewave CDK at about 3000 mm focal length with a Moravian C3-61000 pro camera ?
I have got 3 subs (L, R and G so far) which is about 3 minutes approx in total altogether. I am trying to get more - L, Blue and H-alpha) tonight.
So far, the L,R and G look fine.
Lucky you. That's a very expensive scope. It's way out of my league, and I certainly don't own one.
Nobody reading this has any way of knowing what your definition or idea of a "reasonable image from a 17 inch Planewave CDK" might look like.
Pictures I've seen that do justice to the quality of a CDK17 usually have 10-40 hours of collection data excluding calibration and darks but these may exceed or not meet your benchmark.
I can suggest two ways to proceed so you get some specific information.
1. Use a Search Engine
Google is one such search engine. This article has 23 links to other search engines. https://www.searchenginejournal.com/alt ... es/271409/
You type in what you want to know about and it gives you links to relevant web pages.
You could try searching for images of M104 taken with a CDK 17.
2. Astrobin search
There's an astrophotography archive site called astrobin https://www.astrobin.com/
You can search for photos taken with specific scopes, cameras, or of particular objects.
Most images have a technical card with all the exposure info in full detail.
Good luck with your image production.
I look forward to seeing it posted in the astrophotography sub forum when it's done.
regards
Joe
Amateur astronomer since 1978...................Web site :http://joe-cali.com/ Scopes: ATM 18" Dob, Vixen VC200L, ATM 6"f7, Stellarvue 102ED, Saxon ED80, WO M70 ED, Orion 102 Maksutov, ST80. Mounts: Takahashi EM-200, iOptron iEQ45, Push dobsonian with Nexus DSC, three homemade EQ's. Eyepieces: TV Naglers 31, 17, 12, 7; Denkmeier D21 & D14; Pentax XW10, XW5, Unitron 40mm Kellner, Meade Or 25,12 Cameras : Pentax K1, K5, K01, K10D / VIDEO CAMS : TacosBD, Lihmsec. Cam/guider/controllers: Lacerta MGEN 3, SW Synguider, Simulation Curriculum SkyFi 3+Sky safari Memberships Astronomical Association of Queensland; RASNZ Occultations Section; Single Exposure Milky Way Facebook Group (Moderator) (12k members), The Sky Searchers (moderator)
Hi Joe,
I mean a reasonable image is one that is quite low in noise, can be sharpened and is easy to process. I have obtained some NGC4216 (sn2024gy) subs and also of M104. Unfortunately, the weather and some technical issues mean I have not got many subs. I will post some when the situation and weather improves !
My suggestions would be to spend a few nights on getting your RGB and than a seperate night of just your Lum's and another 1 or 2 nights of your Ha. Your LRGB would be good at 120 sec each but for you Ha (Depending on filter) I would go for 300 sec. A good average is Lums double the number of subs you have for RGBHa
Of all the things I've lost, I miss my mind the most! :tease:
One thing to note, if this scope is in a remote setting and doesn't have a rotator on it, there may already be a set of calibration frames for each filter. If there is a rotator, then all bets are off and you will need calibration frames (flats) each session. If there is the possibility of someone else having access to the scope again before your next session.
30mins TOTAL each night is not very much time when you factor in getting on target, focusing, setting up imaging run, capturing data, then flats (if needed).
I would recommend starting off the first session with 10x120sec for Lum, then flats (if needed)
Repeat this session until you have at least 60 Lum files.
Then keep repeating session for RGB until you have at least 20 for each filter.
Then as Iostone mentioned, probably 300sec or longer for Ha which means you are only going to have time to capture about 4 subs per night. You will want at least 20 Ha subs.
That's a lot of short sessions.
