Quote:
Originally Posted by Ukastronomer
why not a simple altaz mount and refractor
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Cost mostly hehe
Quote:
Originally Posted by Wavytone
Choose the right scope to suit what you want to observe.
I would suggest for a dark site the subjects of interest are DSO’s - nebulae and galaxies not possible in the city. Alternatively if in the city, it’s mainly lunar planetary and bright clusters (mak or SCT).
Having had all of these scopes at one time or another I can say the SW180 and C8 will show DSOs better than some might think but they can never match the wide fields of an f/6 newtonian of the same aperture. OTOH if magnification is your game, the SW180 should do better than others at high power on the planets, but the mak and SCt require a mount that tracks - so it’s really your call.
The dob is as simple as it gets. If you go with an SCT or the mak, you’ll have to assemble tripod, level the head carefully, mount, put scope on top, lug out a battery, connect the wires and handset, align with the pole etc before ready to observe. It takes me 39 minutes and that’s assuming I get it all right first try.
What’s more if you think dew is bad with a newtonian its much worse with an SCT. First mistake is attempting to cool the scope as far as you have done - which is why it dewed over.
Personal experience:
1. the SW180 is that it wont dew over so quickly as an SCT (lots of thermal mass in the thick corrector - which is a good thing).
2. Both SCT and mak should be insulated to stop them cooling - this very effective kills the internal tube current from the central baffle, and keeping them warm prevents them dewing over. Both will benefit significantly from a dewcap. Last resort - if the dew over - is a heater strap inside the insulation around the OTA, and a battery to power it.
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A cass of some description would ride on the HEQ5 which is a pre-SynScan but tracks well. I can eyeball PA to within a degree or so which is enough for observing with occasional recentering so mount setup is a minute or so.
One of my other considerations is exit pupil. I can binoviewing up to about 3mm but for mono viewing I like to keep below 2.5mm otherwise astigmatism becomes distracting on star clusters. Basically, my young eyes suck
95% of my trips to Heathcote are for AP but doing some visual between checking on everything keeps me happy. An 8” F/6 is easy to use no fuss visual and as you mention, dew on the corrector can be a pain. My first telescope was a 10” LX200 which I usually used on concrete to help stave the dew.
For DSOs they’re all the same aperture. For others the 8” dob is push to and has a much smaller CO and is optically simpler. The C8 and SW180 help with tracking and are binoviewer friendly but I’d probably do mono more often on these occasions anyway.
Quote:
Originally Posted by xelasnave
You need to focus on the real problem which seems to be managing storage of the scope.
May I suggest that you leave the base outside under a cover and just put the ota in the van..the issues of dew can be sorted just as easily.
Alex
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If I was up there more often I’d consider it. Some months I’m up there a few times but other times months can pass. Largely depends on the weather and work
