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Hi guys, I'd love to hear your opinion on that: My current gear is a HEQ5 Pro, a GSO 6" f4 and a Canon 1000Da (and of course a little guide scope and a QHY5L-IIc) Depending on how the renovation on my new house goes I might have some money to spend and I was wondering what would give me the most bang for the buck:
There is probably not enough money left to go for both so I am happy to hear your recommendations. I know the first reply will be like "Depends on what you are planning to do" so let me quickly explain that: I love imaging DSO objects and these will be my main targets. However I occasionally love to take a planetary video/image and the f4 annoys me a bit because of the huge obstruction, hence my idea to get an EdgeHD 8". Looking forward to hear your thoughts  Best Frank |
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| Electronics age quickly, while optics last forever if properly cared for. Nothing wrong with 1600, but I would wait for a more refined CMOS camera for dso. My advice: get a telescope. |
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| My feeling is that a HEQ5 will struggle with an 8" SCT. LRGB produces much better results than a DSLR. So I say that unless you expect a mount upgrade in your future, you would be better off with a mono ASI1600 cooled, electronic filter wheel, and the LRBG filter set or the LRGB and HaSiiOiii combination filter set. Narrowband filters makes imaging under light polluted skies easier. It is important to get a field flattener specifically designed for your scope if you go with a ASI1600 because the pixels are small and you will not have enough sharpness with an uncorrected imaging Newtonian to make use of the really small pixels. I have a EdgeHD 800 with a AVX mount. The AVX and HEQ5 are very similar with the only big difference in mechanical features being the HEQ5 has bearings on the DEC axis. The 8" is too big for the AVX even when I use a HyperStar. A friend of mine recently purchased a ASI1600MM-Cool and has had good results. He says he is going to sell his QSI camera which has a KAF-8300 sensor. Anyway my point is I think that the mount is the most important part of an imaging kit, so configure around the mount. |
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| The clear "bang for your buck" option is a cooled mono astro camera. A cooled mono camera will give you a significant increase in image quality and open you up to narrowband imaging if LP is a concern for you. If you want the 1600, Woodland Hills has a sale on the mono version right now for $1,180. |
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Thanks for your answers, it is highly appreciated. Just one more question:the edge HD 8" is only 500 gramms heavier than my current OTA (so around 6.35kg) is this really such a difference for the Heq5? I see people using the heq5 with an 8" Newton here so I thought around 7-8 Kilos including guide scope, cam and filter wheel would be a safe bet as load for the mount. Best Frank |
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| My 2 cents, Get the heaviest best mount you can Pay.... |
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Diego Colonnello: I agree 100%....For imaging you want a mount that has a payload capacity that is double of what your actual payload is. Good Luck Bob |
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| The longer the focal length the more magnification, and the more periodic error and other mount problems will affect the image. A 6"D f/4 is 508mm FL. A 8"D f/10 is 2030mm FL. With a 0.7x reducer a SCT is still 1421mm. An SCT with a HyperStar is almost 2 lbs heavier although it is a 0.21x reducer with 420mm FL at f/2.1 the weight and weight distribution is a problem for a light mount. Most people setup an imaging Newtonian with the camera on the bottom when the mount is pointing at Polaris. This puts the center of gravity closer to the RA axis, and lowers the moment of inertia. A SCT will sit completely above the dovetail bar, so the effective weight is higher because of the effect of the center of gravity being further from the axis of rotation increasing the moment of inertia. |
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Very interesting advise Gilbert, so a bit off topic you suggest I should have the cam towards the counterweight bar? Currently I have it the other way around as shown here http://www.astrobin.com/299720/C/?nc=user I just wonder how I should configure it with my rather long dove tail bar. Best Frank |
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Hi Frank, my advise: As you are new to AP, use your current equipment and collect your first experiences. Learn the adjustment of your scope, guiding incl. dithering, using of calibration pictures, etc. Then try to get the best out of your raw data. And in one year, when you reached the possibilities of your current setup, I would buy a new camera. As already mentioned, a bigger scope will also need an upgrade to your mount. With a 6" Newtonian you have already reached the max load for an HEQ5 for AP. BR Frank |
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| Here is an example of mounting the camera towards the mount. This is the first picture I could find (searching AstroBin when the telescope is the subject is not that easy). Your 6" scope is much shorter than the 180mm in this picture, and your mount is also much smaller. Your latitude is a consideration. When using this configuration it is very important to make sure the camera doesn't hit the mount, and to set the slew limits correctly.The heavier the camera, the more likely a person will use this configuration. One has to be very careful when locking the barrels and focuser because of the natural tendency is for the camera to fall out. |
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Thanks Gilbert, thanks Frank, will consider this. These rainy weekends here always have me wandering off onto the shop sites and it is valuable input from you guys. I would have probably gone crazy and got disappointed afterwards Best Frank |
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Hi Frank, for what concerns the imaging train positioning just make sure that the mount is well balanced in RA and DEC. The only true benefit of mounting the camera on the bottom is that it requires a dovetail and clamps mounted on the scope holding rings and with a dovetail on a configuration like that you have an easier life in finding balance and the possibility to reduce flexures while auto guiding. Whatever choice you will make, ASI1600MM-Cool or a bigger (better?) telescope it will cause an economical domino effect  but probably the camera will impact less. The camera will require filters: LRGB and H-Alpha, OIII, SII and a light pollution filter if you have LP problems and a EFW.A scope like the 8'' EDGE HD will require a dovetail, clamps for the autoguider, a better visual back, a focal reducer a dew shield with heater if you have freezings during winter and in the end it will put your mount to the weight limit. Then you will probably experience trouble with autoguiding because of the mount load and at that point you will think about getting a new mount... it's a spiral, i'm into it too  So I would say get everything but start from the ASI1600MM-Cool |
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Great answer Andrea, it is very much appreciated I feared that it will end up in a bloody spending spiral  So I will take it step by step, will wait for a while now to see how the renovation goes and then maybe around christmas will aim for the ASI.Thanks a lot guys! Best Frank |
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Andrea Alessandrelli: second!! |
