Altair Astro 60mm guide scope star haloes

[Davey-T]

Just got a 60mm Altair guide scope and with PHD the stars all have haloes,  using a Loadstar camera which was OK with an ST80 on the same setup, all that's changed is the guidescope.
Looking into the ojective the inside of the OTA looks to have a lot of shiny surfaces, don't know if this could cause the haloes.

Dave

 

[steppenwolf]

Could it have been condensation on the front element that the short dew shield has not kept at bay? I have used the same finder-guider and found it excellent although the stars are a little bloated but not haloed in any way. The bloated stars have not been an issue with regard to guiding.

[Thalestris24]

Hi

First - do get the latest PHD2! I think the haloes might just be a consequence of it being an achromat. However, it shouldn't interfere with guiding. Your background is very noisy! Are you using darks or a bad pixel map? Having said that, the atmosphere up here has been pretty awful recently and that causes a lot of guide camera noise and affects sub contrast and guiding. Sometimes I know I shouldn't be bothering with trying to image but just to get the occasional chance overrides my realisation that conditions are not really favourable...

Louise

[Daniel-K]

I agree with Mr wolf it's more than like some sort of dew formation.

[Owmuchonomy]

I use pretty much the same set up and it is flawless. Looks like some rapid condensation to me either on the chip or the scope. Did you take it from warm to cold?

[Davey-T]

Had a dew band on the front, checked for dew and it was clear, took the camera out to look and that was clear.
Same thing two nights running but it still guided OK.
Regarding Altair selling this as a "guidescope " why did I still need an 1.25" extension to reach focus ?

Used PHD Dark library Louise, is there a newer PHD ? seems only a couple of weeks since I downloaded this version

Dave

[Thalestris24]

34 minutes ago, Davey-T said:

Had a dew band on the front, checked for dew and it was clear, took the camera out to look and that was clear.
Same thing two nights running but it still guided OK.
Regarding Altair selling this as a "guidescope " why did I still need an 1.25" extension to reach focus ?

Used PHD Dark library Louise, is there a newer PHD ? seems only a couple of weeks since I downloaded this version

Dave

Hi Dave

Yeah, there's a v2.6.1 now

I know I've seen the halo problem with my AA 60mm too (+qhy5l-ii mono). I can't remember if it's still there (I'm getting old!)... It's on my 130pds and I've not used it for weeks... However, I have a SW 9x50 finder guider with a GPCam on the TS Apo and I get haloes with that too. Since I image from indoors there's def no dew, though it does get cold, lol. The common factor is the same mono sensor so it might be due to IR or achromat blue/purple halo! As long as guiding is ok I'm not too bothered. Maybe a focus adjustment might minimise it?

Louise

[Davey-T]

Thanks Louise

Dave

[steppenwolf]

Quote

Regarding Altair selling this as a "guidescope " why did I still need an 1.25" extension to reach focus ?

Ditto!