Celestron 102mm Wide View Astrophotography

Post by **rcj** » Tue May 29, 2007 10:24 am

Hi Ray,

It is out of focus. Also, from the picture, the tripod head looks small compared to the refractor itself. It might be better to put it on something like the 410 equivalent or use a telescope tripod. I have successfully tried doing moon mosaics with the 410 on 190 tripod with a Borg 76ED refractor which is of a similar focal length to the Celestron. Definitely do a mirror lock up, and make as short exposures as you can (below 1/30seconds) to "freeze" the moon. Hat-trick might not be possible here as it does not yield deterministic exposure times, but more for deep sky exposures.

aquillae · Post by **aquillae** » Tue May 29, 2007 2:23 pm

hello, you might want to remove the extra camera flash to reduce some weight.

My 350d / some heavy eyepieces+2"diagonal will change my Orion 80mm's focuser position a bit even though the focuser is locked (this happens mostly when i'm pointing overhead). I fixed this problem with some rubber bands to help compensate downward force.

raychan · Post by **raychan** » Tue May 29, 2007 8:18 pm

Hi Traveler : Oh, not using anything special. Just a normal Nikkor 24mm, 50, 135, 18-70 and the 80-200mm. Thanks for pointing out the typo....a 2000mm with F5 aperture will probably weigh in at 1 ton with a diameter of 3 feet :-D

Hi River & Aquillae : Didn't lock the focusing knob as I didn't felt a need to do so. Afterall, I removed all the unnecessary stuff like the flash and the battery pack leaving only the bare-bone D200 body. The D200 is the lightest body I have.

RCJ : I think you are probably right. The tripod may not be sturdy enough for the scope and my DSLR. As the D200 is the lightest body I have, no point attaching it to my D2X and F4E.

Therefore, will probably scout around for a studier tripod just in case I decide to upgrade to the C130 when my wife goes to US again.

Clifford60 · Post by **Clifford60** » Tue May 29, 2007 8:29 pm

Instead of upgrading to a C130 which is only about 60% increase in light gathering, I think you should go for a big dia like a C8 (4x more) or higher. And may don't even need to buy new, someone in this forum might sell theirs, so your poor wife don't need to carry the heavy monster all the way back plus you will like to pay less.

Post by **weixing** » Tue May 29, 2007 8:33 pm

Hi,

Didn't lock the focusing knob as I didn't felt a need to do so. Afterall, I removed all the unnecessary stuff like the flash and the battery pack leaving only the bare-bone D200 body. The D200 is the lightest body I have.

You better lock it... the focuser just need to move 0.2mm to give you a blur image for a F5 scope.

Have a nice day.

raychan · Post by **raychan** » Tue May 29, 2007 11:27 pm

Hi Cliff.

Wah piang oi.....So fast ask me to get an 8" scope?:-D I'm still a newbie....Hehehe...

I juz started out 2 days ago & still hvn't even open the instructions manual on how to use my 1st telescope :-).

But then, u may be right. No point buying the C130 or C5 as the 1" increase doesn't do much in light gathering. Perhaps the C8 is really a better option.

Will probably get a 2X barlow & try it out for now. Do barlows reduce the brightness of the eyepiece like Teleconverters?

Ultimately, I will need to get either an AZ/EQ mount with a Go-To computer for our next trip to US. Those things weigh a lot, especially if I need counterweights for my DSLR & scope.

Clifford60 · Post by **Clifford60** » Tue May 29, 2007 11:31 pm

Any increase in mag will reduce in brightness. Just post in Buy & Sell and see if anyone can offer you the items you are looking for. Don't need to get everything new. Buy cheap can buy more and can be good too.

Meng Lee · Post by **Meng Lee** » Tue May 29, 2007 11:41 pm

by the way, C130 will give you a big f-ratio (barlow will also increase f-ratio), then you have to adjust your exposure accordingly. Beware of vignetting also when you use a barlow. And Chromatic abberation increases as well.

raychan · Post by **raychan** » Sat Jun 02, 2007 11:48 pm

Thanks for all the valuable feedback.....took some shots tonite of the full moon based on some of your recommendations and noticed that it is slightly better.
As I don't have a moon filter, I set the camera to B/W mode and underexposed it a few stops.

Although it is not as sharp as RCJ's photo of the moon, at least it is better than my first shot posted earlier on.

Noticed RCJ used an extender for his photo of the moon.....where can I get the extender ?

Meng Lee · Post by **Meng Lee** » Sun Jun 03, 2007 12:52 am

"extender" is the Takahashi jargon for (corrected) barlow made for their specific scope. Essesntially, you can put on a 2" Barlow if you want to magnify. IMO, a webcam is the best medium for capturing details on the moon if that's your aim.