Upgrading an AVX - Forums

Topic starter

Feb 11, 2017

Hello and thanks in advance for reading my question.

I am upgrading my AVX mount to a 40 lb capacity mount to improve my photography. I have purchased a pier plate adapter that will accommodate either a CGEM II or an Atlas Eq-g. So the mount will be either of those two and will be used for unguided DSLR photography with fast lenses and my f/4 Newtonian. Also, the future might hold a larger visual instrument such as a C11. I really don't like bringing my laptop out to my pier.

I would appreciate your thoughts/opinions between these two mounts. Clear Skies, Jason

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Gilbert Ikezaki

Feb 12, 2017

Neither the Celestron CGEM II nor the Orion Atlas EQ-G will provide very good unguided performance. Both have native PE of around 40 arcseconds ptp, and that is only if you are lucky to get a good unit. With a great deal of work using CCDware PEMpro you might be able to use PPEC to get down to 16 arcseconds ptp. With a good autoguider you should be able to achieve better than 6 arcseconds ptp PE using a guide scope, or 2 arcseconds ptp using an OAG with a payload of under 20 lbs. Consider getting a Lacerta MGEN Stand Alone Autoguider for astrophotography. It is a good compact guider that does not need a PC. You can buy one from Telescope-Express (on eBay if you live in the US). If you can live with poor PE performance the Celestron handset is much superior to the Orion handset because Celestron's firmware is much more mature. On the other hand the Atlas with open source EQMOD available from SourceForge is much better (but still bad) for unguided use because it has very sophisticated sky modeling; however, EQMOD requires a computer. EQMOD and a PC replaces the handset. The sad thing is $3,000 for a mount and an autoguider is still considered inexpensive for astro-photography.

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Adel Kildeev

Feb 12, 2017

JHolland

Topic starter

Feb 12, 2017

Gilbert Ikezaki:
Neither the Celestron CGEM II nor the Orion Atlas EQ-G will provide very good unguided performance. Both have native PE of around 40 arcseconds ptp, and that is only if you are lucky to get a good unit. With a great deal of work using CCDware PEMpro you might be able to use PPEC to get down to 16 arcseconds ptp. With a good autoguider you should be able to achieve better than 6 arcseconds ptp PE using a guide scope, or 2 arcseconds ptp using an OAG with a payload of under 20 lbs. Consider getting a Lacerta MGEN Stand Alone Autoguider for astrophotography. It is a good compact guider that does not need a PC. You can buy one from Telescope-Express (on eBay if you live in the US). If you can live with poor PE performance the Celestron handset is much superior to the Orion handset because Celestron's firmware is much more mature. On the other hand the Atlas with open source EQMOD available from SourceForge is much better (but still bad) for unguided use because it has very sophisticated sky modeling; however, EQMOD requires a computer. EQMOD and a PC replaces the handset. The sad thing is $3,000 for a mount and an autoguider is still considered inexpensive for astro-photography.

The Lacerta MGEN is attractive to me. That is something I might add in the future.

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