Question Adjusting torque on the Linear

Dear,

I'd like to know who to determine the best torque value.
I was perfectly running with a small T150 and 70% torque (about 8kg).
Now I have a T250 and about 16kg. Well balanced, the mount does not have any issue pointing in any directions but my guiding is not so good (I may have a lot of things to improve).
I'm guiding with an OAG at 1000mm focal lengh.
I was asking myself :
- Does the torque need to be increased ?
- Does tracking adjustment will help me ? (didn't find explanation about how to chose de value)

Dear Stefano,

Thanks for the reply.
I guide with an OAG so focal lenght equal imaging focal: 1000mm.
My sampling is a bit more precise en guiding because I use a 2.9um/pix sensor for guiding and a 3.8um/pix for imaging.

I'll carefully read the manual. Thanks.

When you say your guiding is not good, can you be more specific?

My guiding is between 0.6" and 1" RMS with large peaks sometimes 2" away.
This was not an issue with my old setup which had 1.38"/pix sampling but is an issue now with my new setup which has 0.7"/pix sampling.

It may be related to the OAG which has a substantial higher definition now compared to before and may be way more sensitive to seeing.

Someone had good result with zfilter algo inside PHD2 (the only time I tried was catastrophic so I went back to lowpass2.

Note: I use the parameters recommended by Avalon with an OAG 1000mm focal length.

Guillaume wrote: My guiding is between 0.6" and 1" RMS with large peaks sometimes 2" away.
This was not an issue with my old setup which had 1.38"/pix sampling but is an issue now with my new setup which has 0.7"/pix sampling.

It may be related to the OAG which has a substantial higher definition now compared to before and may be way more sensitive to seeing.

Someone had good result with zfilter algo inside PHD2 (the only time I tried was catastrophic so I went back to lowpass2.

Note: I use the parameters recommended by Avalon with an OAG 1000mm focal length.

I have a similar setup but my focal length is 1500mm and my scale is 0.5. While i never got it stable at 0.5, and usually it is between 0.5 and 1 when it comes to guiding, i never had a problem with the stars being round. My guide camera has a 2.9um pixel size, but i use bin 2x2 in phd2, and I use the subframe option (i noticed that even if i set it to 1.5s exposure time, it takes longer to come in).

On the avalon I use 0.2 for both dec and ra, and the rest similar to Avalon's recommendation of phd2. Although sometimes I set the dec minmo higher, to reduce the unnecessary corrections. I also set in the stargo the RA compensation (forgot the exact name) to -50, which I found best for my setup. Let the auto thing run for a bit and find your value.

That being said, poor seeing or wind can impact my guiding a lot. I end up tuning the parameters in phd2 slightly and I got it under control most of the times.