First light double stack PST

[smerral]

Well I finally managed to get some solar images with the double stack. It really is tricky with the sun being so low. Anyhow here are my first lights. SPC900 b/w webcam and Cemax x1.5.

[Cschur]

Wow, those are fantastic! You did very well id say for your first light.

[Montana]

Wow!!! these are magnificent

Beautiful filaments, and isn't it wonderful to get prominences on the same picture as the surface. I'm really looking forward to many more of these, I'm glad you are getting such good results.

Alexandra

[smerral]

Thanks for the comments! Yes I'm really pleased with these first results. There will certainly be more, especially once the sun begins to climb higher. I also experimented with the BS5 and SM40, but the double stack PST is a clear winner. What's interesting Alexandra is that with the SM40 and BS5 combo the tuning is right at the end of the wheel, whereas when double stacked with th PST it is central. This seems to be the opposite of what you have?

[Photosbykev]

very nice detail smerral

[Carbon60]

Lovely shots. Nice detail with the double stack!

Stu.

[devilgas]

cracking results!

dumb question time though.....the PST and the SPC900. is a barlow required to achieve focus? had a very quick play yesterday when we had 30mins of sunlight but couldn't achieve focus when using the SPC900 direct to the PST (using the morgan's kit supplied adaptor & IR filter). thanks!!

[smerral]

dumb question time though.....the PST and the SPC900. is a barlow required to achieve focus? had a very quick play yesterday when we had 30mins of sunlight but couldn't achieve focus when using the SPC900 direct to the PST (using the morgan's kit supplied adaptor & IR filter). thanks!!

No it's not a dumb question. In order to reach focus you need to get the imaging chip within 5mm of the eyepiece holder. You can do this by re-boxing the webcam and I know a few who have done this. My method though is to leave the webcam as it is and screw a x2 barlow lens onto the end of the webcam adapter. This will give you about 1.5x and you will be able to achieve focus. You can screw the lens off a standard skywatcher barlow, but I use the Cemax which is better quality. I can't bring the image to focus though if I use the barlow in the normal way. However my Tal x3 and, better still, my Televue x2 powermate work fine.

[devilgas]

thanks. i did google it afterwards, but forgot to post here that i'd found the answer. i have the cemax 2x barlow, so if we ever get to see the sun in the near future, then i'll give that a blast. i also have some bits on order to re-house the webcam. an old DAT box will be it's new home with the on-order 1.25" barrel to be attached when it arrives.

[Merlin66]

Re the tuning position....

To get the minimum double stack band width one etalon must be tuned slightly to the blue side of Ha - and the other slightly to the red side of Ha. The resulting, much narrower, bandwidth will then be centred on Ha.

The differences between you and Alex may be down to which etalon is tuned to which position (ie red or blue side)