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I recently scored a great deal on facebook marketplace and bought Skywatcher Skymax 180 mm Maksutov-Cassegrain Telescope (f/15) with EQ6R-pro mount. I understand that long focal length telescopes are more suitable for planetary imaging. However, as I am tight on budget, I would like to use the same scope for deep-sky astrophotography. I have Canon Rebel T5 DSLR camera that I am using for taking images. Without autoguiding and a decent polar alignment, I can get ~30 seconds long shots without any star trailing, but that's not sufficient for imaging objects like M51. I would like to be able to integrate longer, say few minutes, thus would like to purchase an autoguider. Here are some specific questions I have.
1). The telescope comes with an 8 x 50 straight-through finder. If I were to use it as a guidescope, what type of image integration time can I expect? Has anyone done autoguiding for f/15 scope with an 8x50 or other finderscopes?
2). If the integration time will be an issue with the 8x50 finder scope, I am open to purchasing an off-axis-guider. However, considering the narrow field-of-view of Mak-180 telescope, I am concerned about not having enough photons from guidestar for autoguiding. For instance, with my DSLR camera, I need to integrate 20-30 seconds to see the nearby stars in M51. What type of OAG and camera would I need to autoguide with my scope? Are there affordable cameras (~$200) that would do the job for me? Would ASI120MM Mini Monochrome (~$150) do the job? What about OAG?
I plan to use phd2 software for autoguiding rather than relying on the build-in guide port on the mount. Instead of integrating for hours, I am planning to do DSS stacking of few mintues long multiple shots, hopefully this will put less strict requirements on the autoguider.
In case this information is relevant: with my current setup, I have no issue pointing my scope to a desired deep-sky object, track the object within the field-of-view of my DSLR camera for hours using the mechnical tracking of the EQ6 mount. For instance following is a single raw image of Ring nebula taken with 30 seconds shot. But it is not enough for generating high-quality images.
Thank you in advance for your help.
I'm selling a 1 year old Moravian G3-16200M Mark II camera. Please note this is the newer Mark II camera with faster downloads (on my NUC computer it was 9s.). Everything is in like new condition.
The Moravian G3-16200M MKII has a class 2 chip and the standard cooling. The camera cames with an M48 nose piece (unused), power supply with both USA and European plug, 10ft USB cable and hard case. There is also a 17mm extension that can be used if you purchase separately the larger M68 adapter. There are currently 2 read out lines that completely disappear with active cooling and proper image calibration, as is typical with a class 2 sensor.
£2240 PLUS SHIPPING, no fee for paypal. NOTE: ships from USA.
I wonder if someone can please help, I'm fairly new to astrophotography and confused about aperture. Basically I'm looking at a Canon EF-S 55-250mm lens. It has the specs
f4-f5.6 does this mean that the lowest point of aperture possible is F5.6 or will it go lower. What I find confusing is that I have a lens that's the EF-S 18-55mm lens which has the specs of f/3.5/5.6 however My camera does allow me to set the aperture at f/8 The reason I ask cause it is advised to use a low aperture of f/8 to capture images of the moon.
Any help and guidance would be greatly appreciated!
I made an acquisition and processing tutorial a while back (3 years ago? Yikes!) and it is fairly dated in terms of what I'm doing these days. I've been asked for a long time to make a new one showing what I'm doing these days. Specifically how I'm processing a single shot image for both the surface and prominences and how to process them together to show prominences and the surface at once. I've abandoned doing split images and composites and strictly work from one image using layers. Acquisition does not use gamma at all anymore. Nothing terribly fancy, but it's not exactly intuitive so hopefully this new video will illustrate most of the fundamentals to get you started. Instead of an hour, this time it's only 18 minutes. It's real time from start to finish. I'm sorry for the long "waiting periods" where I'm just waiting for the software to finish its routine, it lasts 1.5 minutes and 30 seconds tops typically at first. The first 4 minutes is literally just stacking & alignment in AS!3. I typically will go faster than this, but wanted to slow down enough to try to talk through what I'm doing as I do it. Hopefully you can see each action on the screen. I may have made a few mistakes or said a few incorrect things or terms, forgive me for that, this is not my day job. I really hope it helps folk get more into processing as its not difficult or intimidating when you see a simple process with only a few things that are used. The key is good data to begin with and a good exposure value. Today's data came from a 100mm F10 achromatic refractor and an ASI290MM camera with an HA filter. I used FireCapture to acquire the data with a defocused flat frame. No gamma is used. I target anywhere from 65% to 72% histogram fill. That's it! The processing is fast and simple. I have a few presets that I use, but they are all defaults in Photoshop. A lot of the numbers I use for parameters are based on image scale, so keep that in mind, experiment with your own values. The only preset I use that is not a default is my coloring scheme. I color with levels in Photoshop, and my values are Red: 1.6, Green 0.8, Blue 0.2 (these are mid-point values).
Processing Tutorial Video (18 minutes):
RAW (.TIF) files available here to practice on (the same images you will see below as RAW TIFs):
Video for Acquisition, Focus, Flat Calibration and Exposure (20 minutes):
(Please let me know if any links do not work)
Results from today using this work flow method.
SSM data (sampled during 1.5~2 arc-second seeing conditions):
Equipment for today:
100mm F10 Frac (Omni XLT 120mm F8.3 masked to 4")
Baader Red CCD-IR Block Filter (ERF)
PST etalon + BF10mm
SSM (for fun, no automation)
Just thought i'll bring this up as a point of discussion. Today, cooled CMOS Astro Cameras are available in plenty. QHY, ZWO and other variants of the same camera are selling for very reasonable prices. However, there was a point of time when astrophotographers used to cool down their DSLR's as a cheap OSC alternative to CCD cameras. Give a choice, I would've purchased a dedicated CMOS OSC which can cool to 40 C below ambient, but since I had a Canon 500D which I had self modded, I requested a friend Kaustav Chatterjee (an avid model railroader) to cold mod my 500D (he had cold modded his 1000D long back). This newly modded camera has a TEC12703 single peltier and cools to approximately 20 below ambient.What do you guys think?