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Posts posted by festoon
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Any tips as to how you rotate your camera such that is orthogonal with RA/DEC in e.g. portrait - but keep the back focal lenth the same. When I attach my CCD with T2 extensions the camera is at the correct back focal distance from the lens (Samyang 135mm) but the camera is rotated at an arbritary angle dependent on where the T2 thread mates to the ccd.
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I think both the ASI2600MM and QHY268M are great additions to the market...I'm very tempted
One difference between the models (from the spec I can see) are that the back focal distance for the QHY will be 12.5mm, whereas the ZWO ASI will be 17.5mm. This extra 5mm may make a significant difference in terms of available space for filter wheels or adaptors and also the fllter size choice (e.g. 36mm or 50mm) especially for fast focal ratios. All other things being equal the shorter BFL might lean me towards the QHY model.
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Had a really useful discussion this week regards my all sky camera and optimum settings for catching meteors. But it left me thinking, and wondering about my understanding of imaging settings.
In reference to the Camera I'm using (ASI224MC CMOS) as you increase the gain from say 150 to 300, the read noise goes down from 1.1 to 0.8, but the full well capacity goes from 3000 to 300.
So the dynamic range of the camera goes down by approx an order of magnitude. My understanding of sensitivity is that it is the minimum signal that can be detected above the noise. So by increasing the gain - my question is - are you increasing or decreasing the sensitivity to low light signals. If you take the example of a meteor, which only lasts for a small fraction of a second, do you want a lower or higher gain? What if you doubled the gain from 150 to 300, and halfed the integration time and stacked the two images - would that help you pick out fainter signals? Same thing for a very faint star which is better?
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Makes perfect sense @vlaiv
The GTi rig will be half the weight in the end. Could probably get the EQ35 down to 12kg if you used a carbon tripod, but even still 6kg is a much more attractive option
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One other option which I have come across is the EQM-35 Pro. Seems quite lightwight at 4.38kg. How would you expect this to perform against an eq modified GTi?
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A meteor contrail that lasted 5 minutes!!!! Thats amazing. Was this 23:10 UK time?
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8 minutes ago, tooth_dr said:
I got a similar capture last night, that was the only one of note. I have a little meteor camera that can pick up meteors live as they happen at 25 FPS down to mag +4 or +5 but at 8mm FL. I think the light just gets too spread out on the all sky cameras, which are shooting at 2.1 or 2.5mm FL and F1.6. For example I recorded probably 50+ perseids over 2 nights at 8mm covering a small part of the sky, and got about 4 on the asll sky camera.
I like your thoughts - to try a slightly longer FL. I'm working at 1.55mm at f2
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Last night was out with the kids looking at the Perseid Meteor shower and we saw a cracker of a fireball at 10:35pm (UK time). My all sky camera caught it too close to the horizon.
Reported it here https://fireball.imo.net/members/imo_view/report/203941
We saw quite a few Perseids over the course of an hour or so. Unfortunately my All sky camera (ASI224MC) didnt pick most of them up. I think this is probably one of the most sensitive CMOS cameras out there, so I hoped to record more. However, I guess its because they only last for a small fraction of a second, and its a question of light intensity vs time (Dose) for the meteor to be seen on the image. But if left me thinking - for meteor detection do you want a very high gain to pick out those faint meteors. I guess the down side of this will be increased noise and graininess of the image.
And here is the photo of the fireball from my all sky camera (gain set at unity=135)
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For anyone who has adapted their AZGTI into EQ mode...what is the weight of the mount with a light counter weight attached (enough to balance a photocamera lens and Atik CCD)? And does anyone know how that compares to the weight an EQ3-2 Pro mount or a CEM25P mount?
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Thanks @vlaiv
Can you use ASCOM with a SW adventurer?
Really good point about the AZGTi. I think its a good option. The only issue is I'm not a particularly good DIY'er and I'd hate the thought of bricking £250! Now if someone was prepared to buy and set up the AZGTi mount for me in EQ mode I'd happily pay for their help!
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I'm pretty sure this has been discussed before. I'm looking for advice on which mount and tripod suits my needs most for DSO widefield imaging.
For me portability is key. I'm looking to put together a system which I can leave fully assembled and be able to easily carry. I already have my main imaging rig a HEQ5 and ED80, but more often than not, with me having a full time job and kids I find it takes too long to set up and its not getting the use it should. I also have a AZ-EQ5 which is a bit lighter than the HEQ5 but still its a beast to carry if I leave everything fully assembled. What I'm looking to achieve is a lightweight grab and go widefield imaging set up ASCOM/EQMOD controlled setup that I can leave fully assembled. For this purpose I've started assemblling a widefield low weight rig including a lightweight lens and camera (Atik 414EX and Samyang 135mm F2 lens). If I can leave everything fully assembled and easily carry it into the garden on a clear night, then I think I'd be getter much more data to process
So the question is which mount?
Requirements:
1) EQ mount
2) Weight - including counterweights - fully assembled
3) Able to cope with Focal length 135mm and maybe 30-60 second unguided subs
4) ASCOM/INDI controllable
In the grand scheme of things I'd be happy to spend more money to achieve the most time out imaging, but budget wise probably around £1000. For instance if it eeks a few kg off the weight I'd be happy to substitiute a standard tripod for a carbon fibre one.
I've a list of options in my head e.g. EQ3-2 Pro with a carbon fibre tripod, CEM25P, Explore Scientific iEXOS-100 but I'd really like to hear other opinions...oh and in my dreams https://www.firstlightoptics.com/rainbow-astro-mounts/rainbow-astro-rst-135-mount.html
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1 hour ago, haitch said:
Oh yes you have the comet in an all sky image. That’s the first I’ve seen! Amazing!
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I've built a RPi security camera before that had a built in FTP server and used MotionEyeOS
https://github.com/ccrisan/motioneyeos/wiki/Features
https://github.com/ccrisan/motioneyeos/wiki/Screenshots
** Edit: really useful tutorial https://www.raspberrypi-spy.co.uk/2017/04/raspberry-pi-cctv-camera-with-motioneyeos/ **
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As a simple solution, maybe you could just use an commercially availble security cctv wide angle camera dome for day time sky monitoring
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One point about location...I’d advise you place the ASC somewhere accessible so the dome can be cleaned without too much stress. Birds can make a real mess if they decide it’s a good perching point!
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What is the chemical in the product that warrants this warning?
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Thanks to Jason at Allsky Optics I managed to buy an Arecont Vision 1.55mm 1/2" f2 all sky lens
I have to say its a fantastic lens giving a superb widefield view on my ASI224MC 1/3" sensor. Whats more the sharpness of stars appears great throughout the whole field of view. In my opinion it gives better results that the Fujinon HF1.8HB-L1 1.8mm fl and is light and day better than the all sky lens that was supplied with the ASI224MC camera.
As a comparison the first image is using the Fujinon lens (30/05/2020). This was taken almost a month ago so had much darker conditions. And secondly picture from last night with the Arecont lens (17/06/2020) - still not really dark due to it being mid June UK, but I was very impressed with the images taken
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In Stellarium to sync press Ctrl-Shift-1
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Thanks @fwm891...the pixels which was strange I've tried to highlight in the images below (The object you highlighted is indeed Arcturus, but that wasn't what I though was strange)
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Love this thread @tooth_dr! Here's a meteor captured 26/05/20 at 1:08am, location Cambridgeshire, UK
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Last night there were reports of a fireball event across southern England and northern France https://fireball.imo.net/members/imo_view/event/2020/2602
Upon checking my all sky camera images at the event time I found something - not spectacular (actually rather dull) but could very well be a sighting. It was in twighlight hours and as bright as Vega in this image. The exposure length was 3.5s, so it must have been pretty bright for the short time it was in the sky.
Also earlier on in the night I picked up what I think might be a meteor. The strange thing was that in the frame directly before it I saw an anomoly (red and green pixels) in an area close to where the line originated from. I have no idea what it might be! Coincidence! I have no idea.
Finally, just because I love the Milky Way here's an image from an hour and a half later
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Thanks for the advice Mike @AngryDonkey
I'm convinced that in the most recent image I can see M13 in Hercules! Probably I'm wrong but it does look about in the correct place and a bit fuzzy
Setting CCD rotation for imaging
in Imaging - Tips, Tricks and Techniques
Posted
Thanks @Stuart1971
Glad I'm not the only one who's come across this issue