C9.25 star test at x1175 mag

[Dennis]

Hi Guys

Last night I plugged the x2.5 TeleVue PowerMate and a Takahashi 5mm LE eyepiece into the C9.25 and imaged Sirius almost at the Zenith.

This is the result of 4 frames from 1200 in Registax3.

Focal length of C9.25 = 2350mm.
x2.5 PowerMate increases this to 5875mm.
5mm eyepiece gives x1175 magnification!

The vast majority of the frames were mushy and distorted, but 4 seemed quite round so I stacked them just for the heck of it!

Cheers

Dennis

[matt]

Hi Dennis

That's pretty much exactly what I saw through my 9.25 a couple of nights ago also star testing on Sirius using a 2.5x Powermate and 6mm Vixen LV.

Must have been similar seeing?

[davidpretorius]

i must try this as well, some star test pics would be great for guys to check collimation etc

well done!

it is so much fun mucking around!!

[rumples riot]

Saw the same myself last night. Checked collimation after the big install of Bobs knobs and had a little recheck last night and saw similar images. Nice collimation.

[Robert_T]

1125x, now there's a test of collimation! which it seems your C9.25 passed with flying colours

[rumples riot]

Does anyone else keep collimation records? Once a month I take images of my collimation and compare it to previous months. This way I can assess how accurate I am being with my collimation.

[davidpretorius]

no, but i no mean too!

is sirius a good one for collimation or is it too bright??

[rumples riot]

Sirius is generally too bright for collimation. It is better to use a star around mag1 or 2

[ving (David)]

try rigel or mintaka davo (actually any in the belt)

[davidpretorius]

thanks vingo pingo

[Dennis]

Thanks for all the feedback team, and especially to the C9.25 gang for confirmation that they are seeing similar results - that is quite re-assuring as I still seem to get some soft or low contrast images.

In several of the less distinct and distorted frames, the bright central dot oscillated in a pattern (similar to Lissajou figures) around the actual centre and I thought that my collimation might have been off. But, I just put this down to the results of scintillation during times of less steady seeing.

Wow – Paul; you are a real scientist – keeping records of collimation! I’m still learning after reading yours, and others posts on collimation and I must say, the more I practice the easier it gets as the “fear of tweaking” is displaced with positive outcomes.

Cheers

Dennis

[ving (David)]

Originally Posted by davidpretorius

thanks vingo pingo

no problem davo pavo

[davidpretorius]

no no my pleasure vingo dingo pingo
from
davo wavo ravo.

[rumples riot]

Dennis, thanks for the compliment. I just see collimation as the central issue affecting my images, well at least something I have some control over.