PHD2 "Low mass" star loss while guiding on the slit

[inFINNity Deck]

Dear spectroscopists,

I recently started spectroscopy and have a question concerning guiding on the slit using PHD2. Equipment is a LHires III, C11 EdgeHD, GM3000HPS and ZWO ASI174MM guide camera. The slit is 19 micron.

When guiding on a bright star like Altair or Tarazed PHD2 looses the star regularly due to "low mass". Only when choosing very short exposure times (e.g. 0.2s at 0 gain) it keeps those bright objects locked. The problem then, however, is that PHD2 starts guiding on seeing. So to avoid this, I prefer exposure times of several seconds, but then PHD2 fails. I have to say that I am even newer to guiding than I am to spectroscopy, in deep-sky imaging I never need to guide (I do that at 1050mm and 400mm focal lengths).

I have the mass detection disabled.

Any suggestions are most welcome, so thanks in advance.

Nicolàs

[robin_astro]

Yes I see the same issue of loss of lock where the star is overexposed. I am not sure but I think there is a setting somewhere which allows several short exposures to be averaged (or some kind of filtering of corrections perhaps?)

Cheers

Robin

[robin_astro]

5 minutes ago, robin_astro said:

I am not sure but I think there is a setting somewhere which allows several short exposures to be averaged (or some kind of filtering of corrections perhaps?)

Yes it is the Z filter algorithm. I have not used it before but I might investigate it the next time I see this kind of problem

Cheers

Robin

[inFINNity Deck]

Hi Robin,

thanks, will have a look at that, it sounds like the kind of solution I am looking for.

Nicolàs