Tal 100rs

[wookie1965]

Bit of background the wife knocked this over 18 months ago as there seemed to be no damage I did not worry, After a couple of sessions out I noticed at higher power the view was softer I assumed bad seeing or transparency.

I then did Solar again and noticed I could not get any granulation, as I had had the scope out I left it out hoping for a night session (cut short by clouds) when I went to Vega X125 to get alignment and de-focused I noticed what this drawing shows.

I have had talks with a good friend on here (cotterless45) and John who said check using a laser without the diagonal and with a Cheshire here are the results what do more informed people think. 

I did try with the diagonal and that was out but not by a long way which I have now fixed Just waiting to do a star test now.

[Franklin]

The central laser indicates that the focuser is square on but the cheshire and your drawing seem to suggest that the objective is tilted. Not sure if the TAL 100RS has a colimatable cell but if not you can try loosening the lens retaining ring and gently tapping around the cell whilst ota is in an upright postion. This can help settle the lens back into the correct postion. I had an Evo150 without the collimatable cell and this tube slapping technique actually worked well. Before, the cheshire revealed two overlapping reflections, almost a figure of eight but after doing the above the collimation was bang on and still is to this day. Don't overtighten the retaining ring too much or you might pinch the optics. Hope this helps.

[Stu]

34 minutes ago, Franklin said:

Not sure if the TAL 100RS has a colimatable cell but if not you can try loosening the lens retaining ring and gently tapping around the cell whilst ota is in an upright postion. This can help settle the lens back into the correct postion.

👍👍 exactly what I’ve just suggested to Paul via PM 😀 This worked well with my TAL.

[wookie1965]

Took this with a Cheshire looks OK to me but I'm no expert I did the loosening the ring and tapping around the cell trick. 

[Stu]

34 minutes ago, wookie1965 said:

Took this with a Cheshire looks OK to me but I'm no expert I did the loosening the ring and tapping around the cell trick. 

Hard to tell Paul, I would do a star test when you can see some stars!

[wookie1965]

19 minutes ago, Stu said:

Hard to tell Paul, I would do a star test when you can see some stars!

I thought that if the sun is out tomorrow I can try that at high power I will know if its soft again or not and then wait for a clear night Thursday after 12 into Friday is forecast to be clear so will give it a good test then.

[Stu]

2 minutes ago, wookie1965 said:

I thought that if the sun is out tomorrow I can try that at high power I will know if its soft again or not and then wait for a clear night Thursday after 12 into Friday is forecast to be clear so will give it a good test then.

Sounds like a plan! A lot depends on the seeing for solar obviously so it may or may not be the scope at fault if you can’t see granulation. A star test should tell you more.