NexStar Imaging Showcase
#1176
Posted 17 September 2011 - 06:39 AM
To Alex and all here,
after yesterdays problems, and on reflection over night, i have decided that this will be my last post in the Nexstar imaging showcase. This should be of no surprise to anyone, since i have had this uneasy feeling about posting my images here despite people asking me to continue doing so.
Its clear to me that my image posting upsets certain people,and while i have insisted on posting for those interested in seeing my images, this can no longer be the case, my uneasy feeling is stronger than ever, and so i feel its time i should bow out gracefully.
As Alex is the original poster of this thread and desipte our differences of opinion on this matter i have to respect his wishes that his topic should remain pure to the Nexstar group.
On a personal note to Alex, i wish to say i wish you luck in the future with your imaging, i will be looking in to see your work in Ha, and the excellent work of everyone here.
Regards,
Tom.
#1177
Posted 17 September 2011 - 08:25 AM
Sorry Tel, but the weather will not be good for several days here in France. It's funny because of the same demand than yours on a French forum !
I'm working for a Jupiter's animation but I have a lot of difficulties because of the field's rotation between the first and the final picture (azimuthal mount ). I try with the software named WinJUPOS, but it's hard !
Regards
Eric
#1178
Posted 17 September 2011 - 08:58 AM
OK, 1st off, Thanks Peter, the 102mm is new to me and you know how our skies have been, so it's not had a proper run out yet, but once I've got some good images I'll post a couple.
Thanks Tel for that addition to my comments above, your exactly right on the tight FOV of typical SCTs, and that is infact the whole reason I bought the 102mm, it has a FOV that when combined with the DSLR can fit the whole N Am Neb, Perseus dbl ect, even with focal reducers I came no where near that with the 10", couldn't even fit M31 in there! There just are no jack of all trades in Astronomy lol
Haytor, actually thats why I used to post most of my images in the UK Nexstar Nights thread we setup last year, so I could show my images using the Lunt and Meade (or anything else) in the same place with the same people. Sadly the weather and my superchargering the LX200 has meant I've had nothing to post in what seems like an age. The other sad part is I havent heard from Robbie in an age also
Nat
#1179
Posted 17 September 2011 - 09:08 AM
#1180
Posted 17 September 2011 - 10:01 AM
Nat
#1181
Posted 17 September 2011 - 10:14 AM
First and foremost, I have to declare that I have no practical experience whatsoever of using a Hyperstar with any of our Hyperstar compatible SCT 'scopes, so if you want to venture more deeply into this, I'm definitely not the person to ask !
What I can tell you though, and "Stop me if you've heard it" is that in the first place your 8SE has to be compatible. As of now, some are and some aren't. Those that are indicate such, (I hear), in writing on the secondary mirror. If your particular 8SE IS compatible, this means that your secondary mirror may be removed, (unscrewed), from the corrector plate to be replaced by the Hyperstar unit. When fixed, this potentially reduces the focal ratio from f/10 to f/2, bringing with it a much wider field for astrophotography coupled with a far less exposure time requirement.
Effectively this has converted your relatively "slow", long focal ratio 'scope into a very "fast" small, focal ratio one. However, with this accessory in place, the camera used has to be defined as one probably of the CCD ilk and small in size, otherwise its size will impinge on the light path; remembering that in using a Hyperstar the camera is placed at the front directly over the corrector plate. Thus any excess size of camera body will obscure proportionally the light entering the 'scope.
Such cameras as Starlight Express or SBIG types are the norm. These do not however come cheap !
Hoping that this helps explain a little, but please ignore me if you were already way ahead !
Best regards,
Tel
#1182
Posted 17 September 2011 - 10:37 AM
#1183
Posted 17 September 2011 - 10:48 AM
No, it's hghly unlikely that the cord will interfere at all. It will be well out of focus and as such will not register on the image.
Sure, it will reduce the incoming light minimally but when you consider what area it might represent contrasted with that of the whole corrector plate, such will be negligible.
Best regards,
Tel
#1184
Posted 17 September 2011 - 11:23 AM
Matt, as Tel mentioned, you will need a CCD camera to use Hyperstar. My friend has a high-end SBIG monochrome camera and he spent beaucoup bucks on it. There are some less expensive options though. But bottom-line, you can't use a DSLR on a Hyperstar.
#1185
Posted 17 September 2011 - 01:43 PM
I've seen photos taken with a Hyperstar and DSLR, and you can see that the difraction pattern around stars hints at the shape of a DSLR! It's very strange looking.
If you have, say a 14" SCT, the secondary is much larger than in an 8" so a DSLR is pretty well masked by the round obstruction of the secondary. Check out this photo of a DSLR in place on a 14"
http://www.pbase.com...image/118540988
Matt:
To add to Tel's comments - If your 8SE is Fastar compatible, that means that the secondary is designed to be easily removed and replaced with the Hyperstar lens. If your 8SE is NOT Fastar compatible, you can buy a conversion kit that will make it Faster compatible.
Here's the conversion kit: http://starizona.com...-P2615C648.aspx
Here's the Hyperstar:http://starizona.com/acb/HyperStar-3-Lens---8-Celestron-P991C773.aspx
While your overall scope design is f/10 at 2000mm focal length, the primary mirror of you scope is actually f/2 at 400mm focal length. The secondary mirror is convex instead of concave like the primary, so that's what changes the effective focal length and focal ratio. If you remove the secondary, you're left with an f/2 scope with the image plane a little bit outside the front of the scope's corrector. The Hyperstar puts a lens there to bring the image plane to the right point for the camera, and performs field flattening as well.
The Hyperstar allows you to take pictures with much shorter exposure than normal because it's an f/2 - BUT ... remember it also changes the focal length to 400mm so you're taking *different* images. You get much lower magnification and much wider views so you have to choose appropriate targets.
-Dan
#1186
Posted 17 September 2011 - 03:54 PM
#1187
Posted 17 September 2011 - 05:43 PM
As promised, the animation :
Regards
Eric
#1188
Posted 17 September 2011 - 07:43 PM
#1189
Posted 17 September 2011 - 10:30 PM
-Dan
#1190
Posted 18 September 2011 - 07:26 AM
#1191
Posted 18 September 2011 - 07:57 AM
Thanks for posting.
Regards. Peter.
#1192
Posted 18 September 2011 - 12:06 PM
#1193
Posted 18 September 2011 - 12:31 PM
Best regards,
Tel
#1194
Posted 18 September 2011 - 06:59 PM
Thanks for posting!
#1195
Posted 15 October 2011 - 10:17 AM
This is my first post. I have a NexStar 8SE and a C5 Spotter Scope for travel use. I’ve used the 8SE to do a little AP with the Neximage webcam, but I’ve not been satisfied with the image quality that I’ve been able to achieve so far. Jerry Lodriguss’ recent EdgeHD 11 images of the Moon and Jupiter using a Canon EOS T2i in movie Crop 640x480 mode on his www.astropix.com site encouraged me to try my hand at using a DSLR in movie mode in place of the Neximage. I recently purchased a T2i and just started experimenting with it.
I used my C5 Spotter Scope mounted on the 8SE mount to capture several Moon video clips. I used a Hyperion Mark III 8-24mm Zoom with T2i attached to it with the Baader eyepiece-to-T-ring adapter for easy eyepiece projection imaging. I did this to gain some basic experience using the T2i with an SCT and a zoom eyepiece before moving up to the 8SE. I found the setup quite easy to use and the fact that a laptop was not necessary during imaging provided an extra degree of psychological freedom beyond that of my Neximage experience. I have a JMI MotoFocuser on the 8” OTA, but not on the C5, so focusing was a bit frustrating for my preliminary tests.
The T2i was set Auto movie mode so that ISO and shutter speed where selected by the camera. I varied the zoom over the 24 mm to 8 mm range to get a feel for the overall behavior of the scope-eyepiece-camera combination. The setup was mechanically smooth to work with. I put a Baader 2” SCT Click-Lock on C5 to provide secure attachment of the diagonal-eyepiece-camera train. I used my WO 2” Dielectric Diagonal to provide a comfortable view of the T2i Live View Screen without having to perform contortions to see the camera LCD screen. The SE tripod was in its shortest configuration allowing me to sit comfortably in my observer’s chair while performing the captures. The Moon was used as the alignment target under the SE Solar and Planetary alignment option on the SE mount HC unit. The setup was fast and easy to use.
The T2i’s MOV video clips were easily transformed into AVI format by the freeware program SUPER. Registax 5 was to align, optimize, stack, apply wavelets, and adjust the gamma (curves) to produce the final images.
I concentrated on two Lunar Craters, Plato and Copernicus to perform my preliminary experiments with the equipment. If my memory is correct, these are at a nominal f/20 zoom setting. I’ve included Flickr links to the final images here in case my attempts to attach them in two posts to that will follow fails due to my inexperience with posting here.
Plato image link:
http://www.flickr.co...in/photostream/
Copernicus image link:
http://www.flickr.co...in/photostream/
The preliminary results of using the T2i with the SE setup are encouraging. The Plato image shows at least three of the nominal 2 mile diameter cratelets on the floor of the crater. Perhaps a better Sun angle would make them stand out better? This image was taken 2 days after the First Quarter. I was surprised to be even see them in the image of the Plato since the seeing was just average and C5 is a rather small scope. The Plato video clip was about 75 seconds long at 60 fps.
The Copernicus image was about 40 seconds long at 60 fps. The SE HC was used to keep the crater from drifting too far during the making of the video clips.
The results of this experiment are encouraging. The video clips from the T2i produce more robust stacked images than the Neximage webcam and the logistics of image capturing are significantly less complicated than the working with the webcam and laptop. The weather is now clearing up and I will be able to start using the 8SE with this imaging setup.
Carl
#1197
Posted 15 October 2011 - 10:31 AM
Welcome to the NexStar forum!
Those are some nice images. Congrats!!
#1198
Posted 15 October 2011 - 12:15 PM
Thanks for the compliment on the images.
Carl
#1199
Posted 15 October 2011 - 12:16 PM
You may want to post these in the newer thread called "AP Images taken with original Nexstar". This one had gotten too long, plus it started to mix Nexstar images with those taken on GEM mounts. Alex was kind enough to start two new thread, one for Nexstar images and the other for people who have "graduated" from the Nexstar mount.
-Dan
#1200
Posted 15 October 2011 - 12:27 PM
Thanks for the info on the newer thread. I'll take you suggestion and repost on that thread. I saw the several threads for imaging but wasn't sure which was the best.
Carl