James the essence was the same, not the meaning. You are correct about the reducer or flattener. I am not questioning that ASA make them. Just don't think I will pay for a piece of glass that costs the same as the scope or there abouts.
Carl I concur. With any luck the field of view will have nearly round stars all the way to the corners on the QSI.
Paul
According to the following site http://www.teleskop-express.de/shop/...arz-Optik.html
without a corrector the flat field covers a 30mm circle and with their flattener it is extended to 60mm in diameter.
Worth looking at?
Yes the price is speculation. I don't actually know the exact price. But a 4 inch flattener is a serious bit of kit. RCOS charge about $1200 for their corrector which is not 4 inches but about 2.7 inches. Planewave charge US$1200 for their reducer. A 3 inch Wynne corrector is somewhere around the US$1000 mark. It may be more now as the price would be in Euros and the US dollar has weakened a lot against it.
I bet it is a nice flattener though but more for high end scopes based on likely prices was the point. I am not criticising your post in any way just adding info as these Euro sites rarely announce their prices.
The cost of the ASA RC flattener is EU$1420 (~AU$1900). It is in the pdf price list for the ASA RC scopes, which start at around EU$23000. It is definately not targeted at the GSO RC market.
Paul have you had a chance to go over the build quality ? Whats the focuser like in particular . I am seriously considering the 10" and if the focuser needs replacing then I would go with the Al version and replace it with a FT
and motor for the cost difference over the CF version .
Thanks Allan, I saw an ad for the TS Optics reducer/flattener some time ago but I think it was for the 8" & 10" version.
Greg, if the scope pans out then maybe I might buy a more expensive reducer/flattener. I have to get a star test in first (cloud for miles at present and not looking like it will go away) and do some final collimation. So James you may be onto something, but it does seem like a lot to pay for a reducer or flattener.
Mark, just some cursory things. The smell of the optics are just like when you open a C14. The over coating must be the same product and internally everything looks great. There are no baffles in tube, which is odd but the ray trace may have not needed them on this model. The tube appears to be reasonably thick without being too heavy and all the fixings are what appears to be stainless, but I bet they are just chrome, several months of weather will tell me what is going on. The focusor looks really beefy and just moving the scope via the focusor on a table over looking the valley the image does not go out of collimation. There might be some flex though and as I said before I need to check this against a star test via video (that will tell me what is going on). The ring sets and dove tails seem fine with a reasonable thickness. Maybe some time down the track when and if I modify the scope to a carbon truss I will create a really beefy ali frame to support the whole scope. For now though this seems ok. Overall the only stand out concerns I have is the seam in the tube and the possible flex in the rear assembly. I don't recall ever reading those concerns from former or current 10" owners. If Doug or someone could chime in here it would be great.
Tony, the secondary is 5"I think. Not done collimation yet as the cloud cover has been as per normal this time of year. Hoping to get something done the next week and get the scope up and running. It would be fairly similar to all these scope. If the primary has not moved then collimation is just like an SCT but you need to be a bit more picky. However, not improssible.
I use one of these artificial stars for collimation - something to do on an overcast day and saves mucking around at night. It's cheap and nasty in build but it works well - $25 posted.
With all the drama of trying to get my pointing better on the PME I have not had much of a chance to get the scope tested. I did get some chance at it the other night and ran it around a little. Attached is a single frame with some slight noise reduction and nothing else.
Collimation needs addressing but I did not have time to get it sorted at 3 am. The collimation screws are a bit stiff and this requires a firmer grip than my frozen fingers. One screw is excessively stiff, and needs backing off a lot.
Guide parameters need looking at too. Going from 1.6m to 2.0m in focal length made a bit of difference to the guiding. Some egg shape to the stars but I can live with that for now.
Basic star test did not show any abnormalities but I want to do a more thorough test for the final review.
The image looks quite sharp, but a full imaging run will determine what is any defects there are in the system. I think the focusor is going to be ok, but moving from one side of the meridian to the other will show me whether there is any slop.
Incidently I was using the Tak flattener and this seems to work ok but under CCD inspector it says pretty much the same as for the 8". There is still quite a bit of field curvature but not overly evident to the eye.
Feel free to comment. A thorough analysis of the image is what I am looking for here.
Rather small field though, so testing with a bigger chip would be something worth doing down the track.
I understand CCDI can be missleading at times too.
Mike
Your right big guy. Looking at something larger right now. Looks liek the price is right too. Larger field of view will help with getting stars smaller too.
Not really sure about CCDI either. I often get odd readings from it and yet see no visible issues. Star field plays a big role in findings too.
Thanks for sharing your experiences at the 'deep end' with this ne off the shelf scope.
Excuse my ignorance - is the primary easily collimatable for the GSO?
I can't say collimation is much like an SCT with an RC in my experience at all - however, I have had to deal with construction and assembly of the components from scratch with my RC, so I have a different perspective I guess.
I have found that the two most useful mechanical tools for RC collimation are the Takahashi collimation scope - which RCOS recommends for use with their centre spotted RC secondary mirror and a good 2" autocollimator like the Catseye one. Both of these can assist with aligning the secondary and roughly assessing the rear collar or focuser levelling - assuming it is adjustable.
Fine primary collimation follows with star tests for me too, as you are doing now. Then onto checking images for field flatness etc.
Looks alright for the most part. Only some of the stars appear to be slightly eggy...you have to hunt for them to see that they're there. But if that crop was from the extreme corner of your image, then I would be very happy about that.
Guy, both primary and secondary are fixed in this RC, so collimation really only needs to be tackled with the secondary unless something is really wrong and then you have to use a tak collimation scope to get that primary right again.
Carl, that is not a crop it is the entire field of the DSI with this scope. Scary isn't it?
So Paul you've had a whole weekend to play with your new toy, have you had the chance to take any more images yet? I am following your progress with interest as i am tossing up between the 10" & 12" myself. BTW what was the reason you sold(?) the 8" GSO to buy the larger 12" one?
So Paul you've had a whole weekend to play with your new toy, have you had the chance to take any more images yet? I am following your progress with interest as i am tossing up between the 10" & 12" myself. BTW what was the reason you sold(?) the 8" GSO to buy the larger 12" one?
Yep all weekend, but only one night with some clear skies and that unfortunately reserved for sorting the PME, which I can say is now sorted.
Dave, I will try to follow up soon but I think it will be a month yet before I get another chance at imaging with the 12. I want to use another camera with the scope which is more suited to the narrow field of view. Fear not though, I will get onto this as soon as I can.
I have since withdrawn the sale of the GSO. Initially my thinking was that I wanted to recoup some monies expended but in the end I just decided that this field of view is inbetween the 12 and the TSA. That would suit for more the middle sized objects. So the sale was withdrawn. Besides this is a good little scope and someone I know locally might want to use it from time to time.
Not yet Logan but I am preparing to do the testing and review in this coming month. Now that a favoured target for the job is rising I will be conducting the tests. Some more time yet and I will have a review of the scope for all of you.
