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I should add here that I have no experience whatsoever in doing Photometry ( and very limited experience in DSLR AP). Your comments and help will be much appreciated. Edited by ASTERON (07/30/12 12:30 PM) Post Extras:       gavinm Carpal Tunnel Reged: 08/26/05 Loc: Auckland New Zealand Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5344151 - 07/30/12 08:33 PM Edit   Reply   Quote Quick Reply   It would be a great camera - for the price, almost ideal. The FOV would be small (maybe 10x8' on the LX200) so would want a focal reducer. The chip is small so you could get by with a 0.5x and get a larger FOV - I use the AP 0.67x but I specifically wanted this reducer for its flat field. The cooling is fine. The possible down sides are the smallish FOV and the lack of a built-in autoguider. If you are doing photometry, you dont want RGB filters - the filter wheel only has room for 4 filters and you'll probably want clear plus some photometric filters. Post Extras:       ASTERON Carpal Tunnel Reged: 11/24/07 Loc: ISRAEL Re: ST402ME NABG - suitable for photomery ? [Re: gavinm]       #5344603 - 07/31/12 02:32 AM Edit   Reply   Quote Quick Reply   Gavin, Thanks for the advice. I realize that I wont be needing the RGB filter set but it is included in the deal anyhow. I could also invest in a new BVR filter set carousel available from SBIG for the same camera. While looking at the shape of the filter set I noticed that the openings in the carousel are trapezoidal ? would this prevent me from using 2" mounted filters that I already have in the carousel ? Are there any other pitfalls or other problems that I should be aware of before commiting ? Any comments or advice from owners of this camera are desperately needed so I can make a decision. On another note - are the BVR filters provided by SBIG of good quality ? I've heard that some of them have problems with crude or oxidation residue bacuse of a chemical reaction of the glass with moisture. What types of filters are affected by this ? Another question - is the CCD itself sealed in a chamber to prevent condensation on the imaging chip ? ( is this equipped with a desicant plug that can be recharged by the user (if I need to sent the camera overseas to recharge it will be a deal killer because of shipping expenses!) Thanks for your Edited by ASTERON (07/31/12 02:37 AM) Post Extras:       ASTERON Carpal Tunnel Reged: 11/24/07 Loc: ISRAEL Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5346358 - 08/01/12 02:51 AM Edit   Reply   Quote Quick Reply   Gavin, While corresponding with the seller, I found out that the camera is a 5 years old class 2 detector camera. I asked the seller for some dark frames to see if there are any serious column defects or hot pixel clusters. From what I gathered about typical photometry exposures they will be around 30-60 seconds or so, should I ask for dark frames of this duration? Also will single dark frames of this duration taken at around zero centigrade show me what I need to know about hot and dead pixels? The seller also said that in light frames you get a moire pattern at the edges of the frames and that this is normal for this type of camera. Did you experience such a pattern? Can this get in the way of getting good data for photometry? Is a class 2 detector good for photometry? I need to know if I could subtract any hot pixels by using darks and weather any dead pixels may make the camera unusable for photometry use. Another couple of problems is the camera does not have a power cable and the CCDSOFT software has been registered by the seller so I would not be able to use or sell it if I upgrade and sell the camera. What would be a fair amount of money that I should deduct from the asking price to cover for these missing items? Is there anything else I should ask the seller before buying? I apologize for asking so many questions in a hurry but I simply don't want to get stuck with something I can't use after spending my budget on this camera. As I have never owned or operated a CCD, I just don't have experience to know what to even ask the seller. I will greatly appreciate any help and guidance I can get in making a sound decision on this. Thanks on any and all help Post Extras:       gavinm Carpal Tunnel Reged: 08/26/05 Loc: Auckland New Zealand Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5346468 - 08/01/12 06:21 AM Edit   Reply   Quote Quick Reply   Never experienced any Moire Pattern with my ST7 - can't think why it would be there. I started with a Class 2 then went to a Class 1. Noticed absolutely no difference. My Class 2 had no major column defects, but even if it had, thats no problem for photometry - just move the image until the column defect is somewhere that doesnt matter. Remember that with photometry, you are really only looking at maybe 5 or 6 small regions of the image (the target and a few comparison stars) - the rest is immaterial. In my opinion (others may differ) column defects and hot pixels are pretty cosmetic anyway - ruin photography but little effect on photometry. Dark subtraction removes them. Photometry is all about taking a value from an area so a single hot pixel or two will have little difference. Same comment if there was a Moire Pattern - ensure that the targets are near the middle (not always easy with a small FOV but achievable.) The power cable is a simple 12v centre positive 5.5mm plug. Any 12v power supply is fine and you can get the plug from an electronics store for a dollar. Easy and cheap to wire up, but you may as well try and get some money deducted for it. Same with CCDsoft. I never used it - went straight for MaximDL. (you could have my copy...) Im sorry, I can't comment on a good price - I live on the other side of the world on a small island where there may only be one or two SBIGs in the whole country - they never come up for sale. The KAF-0402 chip is a great CCD for photometry - super high QE and good pixel size. I love mine. It I ever replaced it, I would get an ST8 (4 x FOV, same QE) and use the ST7 for an autoguider. The only issue I know about with these cameras is that the fan sometimes dies - mine did, SBIG replaced it for free but I was out of action for a few weeks. My only negative is that you will need an external autoguider. I hope thats most of your questions. Feel free to ask more. Post Extras:       ASTERON Carpal Tunnel Reged: 11/24/07 Loc: ISRAEL Re: ST402ME NABG - suitable for photomery ? [Re: gavinm]       #5346625 - 08/01/12 09:06 AM Edit   Reply   Quote Quick Reply   Hi Gavin, Thank you very much for your helpful comments. It seems that I would do a sanity check on a few items and if I like the results I will probably take the plunge. Seems like I would have to use an external guider (I have a DSI-II pro which I can couple to a small refractor piggibacked on the imaging scope. I would have to contend with flexture but it seems that I have no choice at this stage. Here are several questions I have : 1) What Photometric filters do you recommend that I get to begin with ? ( is the Filter wheel loaded with the BVR filter set from SBIG a valuable investment ( I will have to buy it new so we are looking at list price +shipping about $300). Should I try to get other filters as well (Used or new) - I intend to end up sometime doing absolute fluence work) and I'd rather plan ahead my filter needs. 2)I would probably want to start with some short period variables so that I can evaluate the performance of the entire setup over a few nights - any recommendations for candidates? - I am situated near Jerusalem ( Guess I'll have to take into account the position of the targets relative to the meridian over several hours). 3) Are you using MaximDL for the data aquisition as well as data reduction ? 4) Are there any additional software that I may need for data reduction and presentation ? ( freeware or commercial). 5) It seems to me that it would be most prudent to start with my AT8RC with AT2 FF Field Flattener mounted on my Atlas EQG and guided by the DSI-II Pro on a refractor and PhD software. Does this make sense ? 6) What reftactor focal length do you recommend for guiding? I have a 90mm Megrez Doublet (f=about 590 mm) , I also have a more lightweight 80mm short tube achro refractor from Orion (f=400mm F/5) Which one makes more sense for guiding the AT8RC + AT2FF - resulting in F/8 and f=1600mm ? 7) I have no idea which Focal reducer to get for my AT8RC yet but possibly a 2" antares 0.5X FR looks OK ? - what do you think ? ( will the AP FF/FR that you use be good on both the AT8RC and the 12" LX200R ? Is field flatness important to photometry or just for astrometry ? 8) The reason I will not initially attempt to use the 12" LX200R is that together with a guidescope+camera+ FF/FR it already exceeds the nominal capacity of the EQG ( 40 Pounds)- is this correct reasoning or am I somehow wrong ? I guess I can go on with questions but I dont want to overdo this. Thanks for your time. Lihu Edited by ASTERON (08/01/12 09:13 AM) Post Extras:       gavinm Carpal Tunnel Reged: 08/26/05 Loc: Auckland New Zealand Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5347729 - 08/01/12 09:28 PM Edit   Reply   Quote Quick Reply   1) Filters. Science is tending towards SLOAN g'r'i filters and away from BVR. V will always be around though. I do exoplanets so (apart from determining comparison star colours) filter choice isnt that important for me. I usually use a clear blue-blocking filter CBB, sometimes Im asked to get data in r' and i'. Sometimes I even use an L filter. I guess start with a V and decide at a later stage. 2) Can't really help with targets, sorry - I only do exoplanets. 3) I use Maxim for everything, except final data analysis and light curve fitting. Then I use MATLAB. 4) There are some good freeware photometry programs - Muniwin springs to mind. Im trying to think of the website that lists them all - if it comes to me, I'll post a link. But I wrote my own software for the work I do using MATLAB. 5) Looks good to me. In my opinion, the most important thing for precise photometry is guiding. I dont use a guidescope, I use the internal guider, and I guide using Maxim, not PhD so I cant really comment on your guiding questions. 6) pass 7) The AP CCDT67 is designed for well-corrected optics like the LX200R and it works really well. CCDinspector gave me a field flatness of about 14%, which is pretty good. I'm not sure how flat the AT8RC is, but it should be pretty flat already, so the AP might be a good choice. Field flatness isnt that important for photometry - small round stars are nice, but a little odd shaped stars doesn't really matter - I got the AP because I wanted a larger FOV. Remember with the small FOV of the ST402, the field curvature will affect it even less. With a larger CCD, it would be more important. Keep the questions coming Post Extras:       NJScope sage Reged: 03/08/04 Loc: NJ Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5347820 - 08/01/12 10:22 PM Edit   Reply   Quote Quick Reply   Lihu: Gavin has offered a great amount of good advice regarding the ST402ME which I've used for well over 5 years for photometry. I'm still using filters (Johnson-Bessell prescription) designed for the ST402ME (BVIc) which allow comparison to a huge database of published data. I've never had problems with these filters which are permanently installed on a filter wheel sold specifically for the ST402ME. Assuming that your main OTA has an 8" aperture then with 1 to 1.5 minutes of exposure you should be able to reach minima at mag 13-14 (V). There are so many targets in this brightness range that it would be fruitless to recommend any specific variable system. Start with ones that have periods less than 1 day and don't have multiples very close to 0.25, 0.5 or 1.0 days since you'll likely end up collecting data from the same part of the light curve for extended periods of time. I use CCDSoft 5 which is supplied with each SBIG camera. You should insist that this software be included with the sale. To give you an idea about software which has proved useful to me, please consider reviewing some of the articles that I have written (UnderOak Observatory). Your suggesting regarding guidescope and software is very reasonable and similar to the external guiding system I used with the ST402ME before upgrading to an ST8-XME. Although a focal reducer can be useful, it is not a requirement in particular for an 8" OTA. Field flatness is more critical to accurate astrometry and shouldn't be a major issue with photometry as long as the target and comparisons stars are not located at the FOV edge. One other consideration is the cooling capacity of a stock ST402ME. I had mine upgraded to the enhanced (-30°C from ambient) thermoelectric system a few years ago. This is a an important improvement over the stock system (-20°C) particular in the summer. BTW unlike the ST8-XME, I've never had frosting problems with the ST402ME. Post Extras:       ASTERON Carpal Tunnel Reged: 11/24/07 Loc: ISRAEL Re: ST402ME NABG - suitable for photomery ? [Re: NJScope]       #5348217 - 08/02/12 06:23 AM Edit   Reply   Quote Quick Reply   Hi Gavin and Kevin, Thank you both for your helpful comments. I truely appreciate your taking the time to help a complete newby in photometry I think between you, you covered most of my most urgent questions. Concerning the enhanced cooling - I think the camera has that (indicated by the fan attached to the back of the camera- in the photos the seller sent me , IIRC, the earlier non-enhanced model did not have the external fan - However, just to make sure, I will ask the seller about this). I will also ask the seller to provide 1 minute and 2 minute darks to check for hot pixels and hot or defective columns - Should I also ask for a Flat to check for dead pixels ?? Is there anything else I should Ask the seller that comes to your mind ? I have some additional questions regarding the filters. I am not familiar with the filter wheel for the 404ME - However, if I buy other separate filters which are not specifically designed to fit the filter wheel of the 402ME, will I encounter a problem in mounting them in the RGB filter wheel that will come with the camera ( What I am asking is, are the RGB filters of the original filter wheel removable ? If they are removable. will I be able to mount another filter(s) instead of the RGB filters, or are they permanently attached to the wheel? Also, if the filters are removable , what size and type of filter should I get that will fit the original filter wheel and be parfocal with the others ? Thanks again Best regards, Lihu Edited by ASTERON (08/02/12 06:29 AM) Post Extras:       NJScope sage Reged: 03/08/04 Loc: NJ Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5348522 - 08/02/12 10:58 AM Edit   Reply   Quote Quick Reply   Lihu: The filters are permanently affixed to the wheel with some kind of glue or epoxy and would be difficult to remove. I would recommend purchasing a new BVI wheel which is reasonably priced ($379). Post Extras:       ASTERON Carpal Tunnel Reged: 11/24/07 Loc: ISRAEL Re: ST402ME NABG - suitable for photomery ? [Re: NJScope]       #5348680 - 08/02/12 12:54 PM Edit   Reply   Quote Quick Reply   Kevin, I needed to know that ! At least this would give me the V filter Which I understand to be some kind of standard filter for Photometry. Thank you Lihu Post Extras:       Ed Wiley professor emeritus Reged: 05/18/05 Loc: Kansas, USA Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5349362 - 08/02/12 09:25 PM Edit   Reply   Quote Quick Reply   My 2 cents: I have a 402ME NABG with the BVI filter wheel and its great for photometry. (Do they make an ABG 402?) Built like a tank. It's a great camera coupled with my 8" Schmidt-Newtonian at F4. Good FOV, great sensitivity, much better than many of the mono cameras. If you have a scope that will give you a reasonable FOV (15' or greater) this is an outstanding camera. BTW, I would not worry about Class 1 or Class 2, but I would make sure the camera has the newer enhanced cooling option signaled by the fan on the back. Ed Post Extras:       ASTERON Carpal Tunnel Reged: 11/24/07 Loc: ISRAEL Re: ST402ME NABG - suitable for photomery ? [Re: Ed Wiley]       #5350505 - 08/03/12 04:49 PM Edit   Reply   Quote Quick Reply   Ed Thanks, this is good to know. I plan to get the BVI filter wheel from SBIG. I can get a decent FOV with the AT8RC by using a Focal reducer. I now know that the chip is class 2, but that's OK with me. I Will let you know when I get the camera. Post Extras:       Ed Wiley professor emeritus Reged: 05/18/05 Loc: Kansas, USA Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5350806 - 08/03/12 08:22 PM Edit   Reply   Quote Quick Reply   Great ASTERON: There is one wrinkle. Occasionally (frequency unknown) the wheel does not seat properly. This happened to my wheel. SBIG fixed the problem for free. You might think about having the camera sent directly to SBIG for a check and filter wheel seating. Ed Post Extras:       ASTERON Carpal Tunnel Reged: 11/24/07 Loc: ISRAEL Re: ST402ME NABG - suitable for photomery ? [Re: Ed Wiley]       #5351247 - 08/04/12 04:31 AM Edit   Reply   Quote Quick Reply   Ed, Thanks for the tip. I will give this some thought. I am limited in the number of times I can send the camera back and forth because of shipping expenses and potential problems with customs. However, I may ask the seller to send the camera directly to SBIG for a general checkover, cleaning and installation of the BVR filter wheel so the camera will be shipped to Israel only once. Do you have any suggestion for any accesories that I will need for photometry so I can consolidate the shipping? Thanks for taking the time to help. Lihu Edited by ASTERON (08/04/12 02:33 PM) Post Extras:       Ed Wiley professor emeritus Reged: 05/18/05 Loc: Kansas, USA Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5352527 - 08/05/12 12:50 AM Edit   Reply   Quote Quick Reply   Hi Lihu: That sound like an excellent strategy. About the only thing I got was a long USB cable, but you can get one locally. The camera should come with a nose piece and software: a disk with CCDOps (good starter program) and CCDSoft and a few other items. Most of my other additions were more software (I bought SkyX Pro and have not regretted the decision as it integrates with CCDSoft to plate-solve.) Good luck with your purchase. Ed Post Extras:       ASTERON Carpal Tunnel Reged: 11/24/07 Loc: ISRAEL Re: ST402ME NABG - suitable for photomery ? [Re: Ed Wiley]       #5352635 - 08/05/12 04:47 AM Edit   Reply   Quote Quick Reply   Hi Ed, Thanks for the thumbs up. I think I May get the long USB cable from SBIG as well as the missing Power cable (unless they seriously overcharge for these items (maybe they could give me a discounted price since I will be buying the BVR Filter wheel and having them check and clean the camera anyways). OTOH, If you know that the cables offered by SBIG are just cheap Chinese cables with the SBIG logo on them, let me know as I may indeed be better off buying high quality cables locally. Another question I have is, does the camera come originally with a mains powered AC/DC power supply ? I need to know that since our local mains voltage is 50Hz/220Volt - so I will need to specify a European Style PS. Best Regards, Lihu Edited by ASTERON (08/05/12 04:53 AM) Post Extras:       ASTERON Carpal Tunnel Reged: 11/24/07 Loc: ISRAEL Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5352701 - 08/05/12 07:06 AM Edit   Reply   Quote Quick Reply   Hi Gavin, Kevin and Ed, Here is the final crucial question regarding the purchase of the 402ME: I posted above that the seller said that the Astrophotos show some Moire Pattern especially close to the frame edges. While Gavin said it does not really matter since I could put the target in the frame's center, I asked the seller for a sample image. He sent me the following link to his astrophotos http://www.astrobin.com/users/Hilmi/ I took a look at the photos and at least two of them (those of M51 and M101 -in B&W) show extensive diagonal stripes which are very prominent and cover almost the entire frame. I therefore ask you to take a look at these Photos and tell me if I should be worried about this Moire pattern causing problems in Photometry Data, as it seems to me that they are all over the frame at least in these two specific images. If you say "No problem" this may be gotten rid off by dark subtraction, or results from incorrect technique or something that can be very easily overcome, I will take the camera. I apologized for keeping bothering you with those questions but I realy wish to start my photometry work with as trouble free equipment as possible, and I don't want to spend my budget on a camera that will be useless for my purpose. So I really need your help on this one. Thank you so much for your kind help and advice P.S. I will also look around in the SBIG 402E user group ( as the seller very fairly suggested that I do. I think I will also ask SBIG themselves. However, I have a hunch that as users of the same Camera who actualy do Photometry work, you may be able to provide me with a quick answer or at least a direction of where to look for an answer. Post Extras:       *skyguy* Pooh-Bah Reged: 12/31/08 Loc: Western New York Re: ST402ME NABG - suitable for photomery ? [Re: ASTERON]       #5352820 - 08/05/12 10:03 AM Edit   Reply   Quote Quick Reply   Hi Lihu, I've owned and used a number of mono SBIG cameras on my 12" SCT over the years and have never seen a trace of a Moire pattern on any of the images I've taken. This is a problem usually found in color cameras caused by the Bayer filter layer when an image is under-sampled. The diagonal stripes in some of the images could be caused by a local electrical interference or a problem with the camera's electronics. It's also possible that the CLS filter used in the images isn't optically flat or slightly tilted with respect to the ccd chip and causing an interference pattern. Not likely, but you never know until it's checked-out. Also, some of the "blotchy" images could be caused by frost forming on the ccd chip and not just light pollution. Personally, I wouldn't buy this camera until the source of the interference pattern is identified and corrected. It could be a simple fix or an expensive one, but that should be the responsibility of the seller. BTW, I've had great success using a SBIG ST-9E camera on my 12" SCT for astrometry and photometry work. It's large pixels are a good match when imaging around 1900mm. FL and the much larger chip (over the ST-402ME) makes finding useful comparison stars very easy. Used cameras don't hold their value and usually go pretty cheap. Even an old parallel port model would make an excellent camera for photometry. Good Luck ... Jim Post Extras:       ASTERON Carpal Tunnel Reged: 11/24/07 Loc: ISRAEL Re: ST402ME NABG - suitable for photomery ? [Re: *skyguy*]       #5352975 - 08/05/12 11:44 AM Edit   Reply   Quote Quick Reply   Jim, Thanks for joining in on this issue. I am afraid it would not be the easiest thing to identify the source of the Moire pattern. The Seller is located in Oman and I doubt he would agree to ship the SBIG for checking out and fixing this if this is not normal behaviour, let alone fixing this at his expense if it is found to be abnormal. BTW- I would love to get me a used ST-9E or even a used ST 8 The problem is - It is very hard to find one for a reasonable price ( What with the need for an 8 position External Filter wheel and a set of filters) and if you do find one - the seller would not agree to ship overseas However, your warning will be seriously taken into account, I will wait and see what the other guys say about this before I commit on this deal. Thank you. Post Extras:       Pages: 1 | 2 | 3 | (show all) Previous   Index   Next   Threaded   Extra information 1 registered and 1 anonymous users are browsing this forum. 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