I am wondering whether other QHY8 users are encountering reflections like this in and around the Horse, Flame, Alnitak. The image is with an ED127, prime focus. No filters, flatteners, reducers or anything else in the optical path except the front filter on the QHY8. But I find it difficult to figure how that could cause the strongly directional blast from the top left. Any ideas?
Peter
Hi Peter, This was a reflection I used to get when imaging this area. It is probably just a bright star just at the right position to impart this reflection.
Since moving the IR filter out to the end of the camera adapter and changing to a low reflection Baader filter I don't seem to suffer this any more.
Peter, The halo around Alnitak is standard fare for a QHY8's front filter. I've never heard of someone imaging the horse head with a QHY8 and not getting that reflection.. It will happen on other stars to lesser extents, M45 is a good example... As Doug said, ditching the standard optical window from the QHY8 and using a Baader filter will resolve that issue..
The light rays coming through the image are caused by Alnilam, The next bright star up from Alnitak in Orion... It will have been within the field of view of the telescope, but not on the camera sensor. Thats whats caused that... Unfortunately, there is about 3/335ths of absolutely nothing you can do about that other than reframing your target so it doesn't happen...
Reflections are the bane of an astrophotographers existance..
Well, that blast top left aint Alnitak, how could it be?. And there aint another star in that direction bright enough. Do you have light leakage through a coupling?.
Fred - Alnilam is in the direction that the blast seems to be coming from, Its only slightly dimmer than Alnitak, and given that the refractors FOV is not completely flat, this would accentuate the reflection. I would bet anything, dollars to doughnuts, that the reflection is caused by Alnilam.. If it were a light leakage somewhere, these ray like reflections would appear in all images, not just the ones of IC434, or at least, so I would assume.
Hi Peter, same problem first time I used my Orion Starshoot. Big beam of light from Alnilam - check out this image. Look familiar? Reframe the horse and it goes away.
. Thanks everyone. I now have a Baader UHC-S filter so I'll go down the road of taking out the standard nosepiece filter from the QHY8 and replace it with this. I'll see how that goes.
Peter
Well, that blast top left aint Alnitak, how could it be?. And there aint another star in that direction bright enough. Do you have light leakage through a coupling?.
Correct. It's not from Alnitak. It comes from the the central star in the orion belt, next one up from alnitak. Flocking gets rid of that kind of reflections. Flock the tube + focuser barrel.
. Thanks everyone. I now have a Baader UHC-S filter so I'll go down the road of taking out the standard nosepiece filter from the QHY8 and replace it with this. I'll see how that goes.
Peter
Peter to gain any decrease in reflection you will have to place the filter at the end of the camera adapter. This then brings it's own problems with moisture in this extra air space. I find if I blow the entire area clean and dry with a hot hair dryer this usually is enough to prevent frosting. The other thing I found useful was to remove the foam packing around the cold finger and replace it with closed cell foam with a larger opening which allowed more of the cold finger to be exposed and freeze any remaining moisture quite quickly.
I hope this is of some help to you and give you some food for thought.
I'm confused - each thread linked back to the other!
By the way, what is flocking? Sounds like something you do to sheep
Pete
No that's NZ flocking. We're talking about good old aussie flocking here which is lining the tube with a dark anti reflective light absorbing material to get rid of stray light and reflections so you can increase contrast in your pictures.
No that's NZ flocking. We're talking about good old aussie flocking here which is lining the tube with a dark anti reflective light absorbing material to get rid of stray light and reflections so you can increase contrast in your pictures.
Sits back and waits for some Kiwi to take offense.
Peter to gain any decrease in reflection you will have to place the filter at the end of the camera adapter. This then brings it's own problems with moisture in this extra air space. I find if I blow the entire area clean and dry with a hot hair dryer this usually is enough to prevent frosting. The other thing I found useful was to remove the foam packing around the cold finger and replace it with closed cell foam with a larger opening which allowed more of the cold finger to be exposed and freeze any remaining moisture quite quickly.
I hope this is of some help to you and give you some food for thought.
Not sure about the 'cold finger'. Is this something you get from your mother-in-law or in road rage situations?
I recently bought from Theo (Gama) one of those heater collars that screws into the QHY8 on top of the filter ring. I'm planning, as a first step, to unscrew the filter and put this heater ring directly in its place, and then screw the filter onto the heater ring (effectively taking the filter another 7mm or so from the CCD). t will be interesting to see if this is sufficient. Otherwise, it seems I'll hav down the road ote to go I
hers and yourself have mentioned, of putting it at the end of the camera adapter.
I'll report back but the weather has closed in again up here so it may be a week or so.
No that's NZ flocking. We're talking about good old aussie flocking here which is lining the tube with a dark anti reflective light absorbing material to get rid of stray light and reflections so you can increase contrast in your pictures.
