SGP & Altair Astro 269c Protec settings

[KeithJohnson]

Hi ' Could someone help me out please? 

I've owned the Altair Astro 269c Protec for about a year now but I "still" don't know the correct camera settings in SGP,

The gain readings range from 1.00x to 50.00x

The black level/offset range from 0 to 496

The USB speed range is 0 to 3

I'm using v 1.4.147.0 ASCOM driver. 

I don't use Sharpcap , APT, NINA so I have not carried out a sensor analysis plus the readings which people use with NINA, Sharpcap & APT don't have the same figure readings as SGP 

Thanks,

Keith.

[Adam J]

On 17/01/2023 at 20:19, KeithJohnson said:

Hi ' Could someone help me out please? 

I've owned the Altair Astro 269c Protec for about a year now but I "still" don't know the correct camera settings in SGP,

The gain readings range from 1.00x to 50.00x

The black level/offset range from 0 to 496

The USB speed range is 0 to 3

I'm using v 1.4.147.0 ASCOM driver. 

I don't use Sharpcap , APT, NINA so I have not carried out a sensor analysis plus the readings which people use with NINA, Sharpcap & APT don't have the same figure readings as SGP 

Thanks,

Keith.

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 

Edited January 19, 2023 by Adam J