Adam J

Depends how its measuring SNR. But a SNR of 1:10000 seems unlikey as thats almost what i would expect from a daylight image lol. Adam

My guess would be that the values the SGP is using are relative gain so 100 = 1x However, the camera has two read modes. LCG = Low Conversion Gain and HCG = High Conversion Gain For DSO imaging you want to be using HCG and I have no idea how you select that in SGP. It may be that it sets HCG automatically for gain values higher than 200 according to some documentation, but even that is complex as some imaging software will perform the mode switch automatically and some will not. Unity Gain is what you should use for RGB imaging and that is gain 282. That would correspond to a relative gain (assuming that is what SGP is using) of 2.82 of if SGP is using dB 4.52. However that could result in a relative gain of 5.65x if switching is automatic. So you need to find out what units SGP is using for gain and if its automatically switching from LCG to HCG. The end point for me with this is that the SGP implementation is a mess and so perhaps you can just set gain in the ASCOM driver instead of in SGP? In terms of such problems I would call this yet another reason to convert to NINA from SGP. As in NINA you just use the 100 - 4000 gain range and you can reference that the the sharpcap sensor analysis charts that have been published. It seems to me that as you have paid good money for SGP they should be bound to help you if you send them an email. Good Luck Adam

So it's actually in the auto meridian flip settings within Nina not the sequencer bit. https://nighttime-imaging.eu/docs/master/site/advanced/meridianflip/ Adam

Huum I thought it was one of the standard options I'll check for you later.

No it will be fine. I would not use pure isopropanol though as it's way too volatile and tends to evaporate before it actually dissolves oils ets from the sensor. Normally want to mix in some other stuff including distilled water to reduce volatility. It's why I use baader fluid. It's expensive on a per volume basis but you don't need lots and it's mixed correctly for you. Adam

Just software bin the 2600mc after stacking. With the low read noise it is almost as good as CCD binning anyhow. Adam

It will do with the native flattner but not the reducer, the larger of the riccardi reducers might do it, but you would have to check. With the large pixel size of the 2400 it might be ok to use with the flattener though? Adam

The problem with using the HFR option alone is that you can have situations when a couple of bad subs or high level cloud will cause a refocus when none is needed and indeed in some cases could make it worse. Personally I always manually choose when to refocus but over the years have learnt the temperature shift that has to happen in order to require a refocus on my scopes. This is something that is easier if you are using a temperature probe somewhere in yoursetup. I personally would never assume that my system (not filters alone) are parafocal in LRGB or SHO for that matter. This is because its about more than just the filters and I want the best focus possible in each channel. So I always set to refocus on filter change. It also makes sense to me to refocus after a flip as you have stopped imaging anyway to perform the flip and so I find it worth while. This is especially the case as you can get into a situation that the system is looking at different stars before the flip to after and so the base HFR changes post flip. It also negates any possibility of the focuser itself shifting during the flip. Adam

I would say that's quite strong especially if you have a unmodified DSLR. I have a FMA180 which has some CA I correct using a L3 filter but the L3 is wider than the standard filters on canon DSLRs and so I am not sure it would help much here. I don't remember seeing someone complain of this level of CA from 62ED before although it clearly has some..it's not totally unknown for some example of a product to perform worse than others due to spherical aberration that is poorly balanced with wavelength (spherochromatism) it usually results from incorrect spacing between the two lens elements. Might be worth contacting other members with the same scope and if they find your results unusual then get in touch with FLO and they should be able to have it tested for you. In all honestly though it may just be like this. Manufacturer's have started to really push the limits of what they can get away with calling apochromatic in recent years.

You say your stars are elongated, can you post a image, preferably unprocessed single sub. In so far are i can tell that 178mm is simply the available back focus in the system, so just the amount of equipment that you can place infront of the sensor while still being able to achieve focus without needing to rake the focus tube in too far. As the scope is a flat field refactor it should not matter what the back focus is. Now if you are using the 0.73x reducer with the scope instead of using it a native focal length you will need to place the sensor 72.2mm behind the reducer to achieve a flat field. Also you would need to compensate for filter thickness. Does that help? Adam

It looks like pinched optics, its the only way you will get star shapes like that. Its not tilt as that would not notch out the star halo like this. If its not happened before was it very cold when you collected this data? Adam

Dont think that meets OPs requirement of being light weight though? The AZGTI would definetly die with that on it. Adam

Am with Vlaiv here the right one is more detailed and natural.

Yes but with the 90FL it causes CA and with your current scope it will not. Yes its about as light weight and compact a 90mm as you are going to find. But it would not be my choice as a imaging scope. Florite is better than FPL-53 for sure, but its still a doublet, so in the end its going to perform better than something a 80mm F6 doublet, but not massively better. I wont say dont go for it, I am just saything that you cant expect perfrect correction from a 90mm doublet at F3.8 even a florite one. Adam

As your using it at F3.6 i would say that you should expect an amount of CA when imaging with the 90FL. For good correction you need to run it at native focal length. Adam

Looks like twisted spider. Just rotate them till they are perfectly edge on to the optical axis.

impressive dedication to a facinating project.

You are missing nothing, these days I don't hear about many issues with the to be honest. They did have some issues early on (3 years back) but then so did ZWO. I would be happy to purchase one.

Ok my advice here is that your biggest issue is the scope not the camera, others have said get a 130pds and a corrector. Use the D3100 for the time being. This is a vastly better combo than a mak and a ting 585 sensor. Of if you want to go wider a 60mm refractor. Sell the mak to help fund it you should get 200 used. Adam

I was running the camera at -20c and only 15% cooling power.

Probably better off making a new thread in the equipment section. Scopes / Whole Setups.

I think that another thing that has not been fully covered is storage, I use a 1gb drive on my mini PC and can store multiple targets worth of data and move it over the network to my laptop. As far as I am aware that is simply not possible with ASI AIR and you are stuck with just a SD card that you need to physically move between the imaging system and your PC. Adam

Yes I agree, I find the stars are part of them image where as some see a nice starfield as a blemish.

Bite the bullet and work through the issues in Nina, when I changed from APT to Nina it was not plain sailing but it was worth the effort.

Your suffering from a classic case of buying everything at once and then not knowing how to work it. Most people incrementally add equipment and hence complexity buying it little by little. NINA is better, ASI Air easier but it's limitations may bug you as you get more experienced. Also with ASI air your locked into ZWO kit and that's really annoying and limiting in my opinion. You would need to buy a ZWO focuser too for that reason. My advice is stick to Nina and solve one issue at a time. Adam