Jammy

I'm thinking about mounting an ASIair Pro to the counterweight bar of my Star Adventurer. It will help balance up the Star Adventurer when using it with small scope, and also allow me to control the camera conveniently. Anybody done this or anything similar? Wondering if there are any such fixings that clamp to the counterweight bar? The ASIair has both a 1/4" tapped hole (same as a dslr) and a finderscope type shoe. The counterweight rod is 12mm diameter. Thanks

Thank you. I've been to and bought astro equipment from RVO, but wasn't sure if they would help with this sort of thing. I'll give them a try. I'm a little further than Scunny, but still my nearest astro specialists.

I know this is a really old thread, but when you say collimated, but mis-aligned; does my photo show what you are thinking? I'm starting to think my secondary mirror is off centre.

Good question! I thought it was reflections of the focus star, but I've been told by someone in another forum that it is called a Poisson spot. All to do with light waves. I've looked it up and there does seem to be something in this. I did an internet search and ended up on Cloudy Nights where there were a few threads about how the spot should be central, and if it isn't your scope is out of alignment. Honestly, I don't know what to believe. All I know is that my scope is showing good shape stars in some areas, and not others. They're not terrible, but noticeable when imaging. I was wondering if anyone else here had ever seen this, and if it was a problem, then how to correct it. Does anyone know a good scope doctor?

Do you think there is something out of alignment? I was thinking about taking it to a specialist, but not sure where to find one in this part of the country.

I've been attempting to image galaxies with my C9.25 rather than my 80ED to increase image scale, but my stars look like they're trailing slightly and I'm wondering if this is down to an off centre secondary mirror. I did accidentally rotate the secondary mirror over a year ago, but I've not used the scope until recently. I've attached an image of a de-focused star that I've used for collimation (near the zenith). In this image should the spot within the collimation rings be central rather than over to one side? Is this the result of an off-centred secondary mirror? I've taken 10 second shots of star fields and they still show slight comma , but don't see how this can be down to tracking error in such a short period of time. Has anyone seen this before? Thanks for any help you can offer.

I've never had any success with my C9.25 when trying to get DSO's. I've seen images other people have taken and they have good round stars. I can never get these. I've tried collimating the best that I possibly can, and adding the Celestron f/6.3 focal reducer but I still can't get round stars. I could understand it if the stars at the edges had comma, but the stars near the centre are showing comma too. I've changed my back focus both in and out to no real difference, I'm just wondering what I'm doing wrong? I took the two attached images last night. One shows my out of focus star from the camera, and the other image shows an integration of 120 x30 sec subs of M63 Sunflower Galaxy. The camera is an ASI 1600mm Pro. These are both full frame, not cropped. When I've plate solved the individual frames for M63 they give a focal length of 1483mm. 1480mm would be f6.3 on this scope, which the focal reducer is supposed to give indicating my back focus spacing is about correct. One thing I have noticed is that on the focus star the rings are concentric and clean, but the small reflections inside the smaller ring are not central. Is this normal for an SCT? I'd have thought the central reflections would be centred too. I've wondered if the star comma was down to guiding errors, but would a 30 sec sub-frame show this much error? Incidentally, my guiding last night was the best I've ever had and I don't think it was down the guiding. When I use my refractor (although shorter focal length) the stars are perfectly round with this mount - NEQ6. A few years ago I removed the secondary mirror to remove a large dark mark from it which was obscuring my views (it was a fleck of black paint from the inside of the tube). When I removed the secondary, I accidentally rotated it when unscrewing. Would this make a difference? I know that the corrector plate shouldn't be rotated, and wondered is it was the same with the secondary? I've searched online but can't find an answer to that. I love this scope, but hardly use it nowadays because of the image quality. Hope someone can offer some helpful advise. Thanks

Thanks Olly I've used the APT flats aid to get to the average ADU exposure times. The flats panel has worked pretty consistently so far. I think you're right about the gain having to be the same. Astro Pixel Processor has thrown a wobbly in the past when I've used a different gain value flat to dark flat. Do you keep your old dark frames, or just the masters?

Rather than release the clutches I point mine to a star near the zenith, which is easy to do with goto. I don't think there is a right or wrong way really.

Hi all. I've created my own darks library for my ASI1600mm Pro. Various gains and various exposure times all at -10 Celsius. I'm just wondering what people do with them? Once you've taken darks and processed an image you get your master darks. Do you guys just keep the master dark, in a master darks library, or do you process your darks again each time you stack a new image? I'm just thinking to save storage, could I discard the dark sub frames and just keep the masters? I don't want to throw them away if that is wrong though. Also, with this camera I take dark flats rather than bias frames. Because the scope is covered, do I need to do dark flats each time I take flats? I have an even illuminated flat box which I always use at the same exposure lengths. I guess the only thing that could vary is the gain value. I understand the need for flats every time you change focus, for each filter etc., but if I'm using the same exposure time can I just use a previous set of dark flats as long as the camera settings are the same? If this is possible, can I then create a dark flats library for any difference in gain values? Not sure if I gain values affect dark flats though. I've read that back, and that's a lot of questions! All help greatly received.

Thanks for the response. I've not used PI, and can't really comment. APP doesn't cope very well with the banding and that's why I've noticed it. I have the same issue even at bortle 6/7. My L subs start to blow out above 20 secs, that's why I wanted to lower the gain value.

I didn't know that. I've only tried because I've seen other people getting good results at gain zero. I'll be completely honest, I've no idea what it is supposed to do if anything. I've asked the same question on one of the ZWO forums and I've been told the camera does not perform well at gain zero and it's been suggested using at 75 gain. I tried it at 75 gain last night, but I'm just running off some darks and flats to see if its any better. I did the Sharpcap sensor analysis and smart histogram and it gave 138 for unity gain (ZWO say 139), and 59 for high dynamic range value. I'm not sure what HDR is or does. I'm a novice when it comes to these type of cameras.

Also, having gone through the whole learning curve of imaging from web cam, dslr and cooled cam with PC, drift aligning etc... I can't believe how simple this makes everything. Have a little patients with it and most of all enjoy!!

I've been trying to image M51 with Evostar 80ED and ZWO ASI1600mm Pro cooled camera. I've used the camera at unity gain at -10C many times and it's always worked really well. As an experiment, I've decided to change the gain to zero to see what difference it makes. I've also added a IDAS D2 LPS filter and increased my exposure time from 20 secs to 60 secs. In bortle 6/7 skies data was blowing out above 20 secs of Lum before I got the LPS. All my images are now coming out with vertical banding. Is this due to the camera gain value? I've added some shots of what I'm getting out of the camera: Single Light Frame Master Dark Master Dark Flat Master Flat (ignore all the dust spots!) Output file from APP without any further editing. My flats and dark flats are taken with a light box at around 1/10th sec, is that too short? I'm getting the required 20000 ADU value at that for Lum. I've not noticed any problem with the camera at unity gain, but having seen other people using gain zero for images and thought I'd try it. Any help would greatly be appreciated, thanks.

They've not updated the user manual from the first version yet. It is very easy to use once you get to know it, and all the steps are pretty much in sequence. I'd have a play about with it and get to know it. I know that's not what you wanted to hear, sorry. There are lots of youtube videos on how to use it, and also a ZWO ASIair FB group which is pretty good, ZWO use it themselves to communicate info about the device. (Not sure if I'm allowed to say that in here - mods feel free to delete this if that's against the rules??) The manual is found on this page, but it is out of date. I believe they're working on an updated version: https://astronomy-imaging-camera.com/manuals-guides