Nik271

A few more easy and spectacular double stars: Albireo, Almach, Eta Cass, Gamma Del, the double-double in Lyra, Polaris. They are visible even in light polluted cities and require only moderate magnification.

Thanks! This seems to be it, indeed this peak has 800-1000 meters difference in height from the rest of the rim walls, and the collapsed section is just next to it.

I was looking at the Moon and Mars through the mist this moring. The seeing was excellent but the Moon was dimmer than usual because of the mist. I went up to x250 with my 127 SW Mak and the view was holding up, just getting a bit too dim. One remarkable thing was the 'church spire shadow' across the flloor of Plato. I dug up the simulated view from SVS at Nasa and it was exactly what I saw: It must be some rock outcrop on the rim casting it. Never seen this before, the Moon always has a surprise for you! Clear skies! Nik

I think light pollution in the atmorphere will be a big limiting factor, even in dark locations the sky is not that dark (mag 22 usually ) and most people live in cities. Where I live the sky is Mag 19, so can't really go very deep. Then there is the issue of calibrating the images with read and thermal noise from different sensors. The BAT is more reasonable, it's trying to do lucky imaging for DSOs, so only short exposures needed. It is not aiming to go deep, but improve imaging DSO resolution to 1 arcsecond and below.

The first question is: what kind of objects you would like to observe? For deep space stuff the Dobs are the best; basically you need a big mirror to collect more light. However if you have a lot of light pollution where you live a big Dob may not be ideal. Simialry if you prefer planetary, then a 4 inch refractor or a 5 inch Mak or SCT could be better choices.

It won't be wasted since these things are great adapted into guiders, some imager will use it.

The advantage of Autumn - no need to get up early for a morning observation, it's still pitch dark at 6am 🙂 This morning I observed Mars at 6:30am with my 127 (120 really) SW Mak and the seeing, while not great, allowed for quite a lot of detail to be seen at x185. Initially as usual Mars was blindingly bright in the eyepiece but after a couple of minutes I started to see detail. There were large dark area both in the south and north of the disc and I guess these were Mare Acidalium and Mare Erythraeum. The north polar hood was showing well and in the south polar region there seemed to be some haze. It's difficult to be sure, Mars is so tiny even at x180 and the seeing was not the best. I found this excellent annotated map of Mars from 2020 from Pic du Midi for reference: At 7am it was getting light and before packing I looked at the Moon, some good detail was showing, especially the terraced wall of Maurolycus in the light of setting sun, and the clock hands of Rima Hyginus. Yet again I'm very impressed with my 127 Mak at planetary observing, for its size and weight it shows so much! Clear skies and good seeing! Nik

Perfect exposure on the the last two, the moons are clearly showing!

A light mist is always a good sign, especially for targets higher up in the sky. Some of my best views of planets and double stars have been on nights when can't see near horizon from fog, but near the zenith the stars are still showing.

I think we should send a SGLer on the next trip to the ISS with a decent scope and mono RGB camera set-up to answer this for us. 🙂

I use the Skymax 180 regularly on EQ5 and the dovetail has never caused any trouble. The tube itself is steel rather than aluminum, 1.6mm thick so it should be able to bear the weight easily. This is one reason why the Skymax is so heavy (just under 8 kilos). I don't have the CC8, it has some very good reviews. It does seem to be more rebustly designed and a bit bulkier. Any of these scopes will sit on EQ6 with ease. The main drawback of the big Mak Casses is thermal equilibrium, best stored in an unheated observatory or shed. The CC8 is more readily deployable.

You will see plenty of stars then in your location. So you could stick with a RDF (could upgrade to a better one like the Baader skysurfer 3) and use the lowest power EP on the scope once in the general area. I find that nothing beats a RACI 9x50 finder though - you can see down to mag 9 stars with it, it is almost a mini telescope on its own.

Yes, one side of Iapetus is much darker than the other, for reasons which are still not well understood. Iapetus is tidally locked to Saturn and and thus its brightness varies with the same period as its rotation around Saturn (about 2.5 months I think). The interesting thing is that the dark Iapetian half is not the same as the hemisphere facing Saturn or opposting it, otherwise the maximum and minimum of brightness will occus at conjunctions. Since they happen at elongations people guessed and later it was confirmed by probes that the dark hemisphere is the 'forward' facing as Iapetus goes around Saturn. So an observer on Saturn will see something like a Yin-Yang Iapetus which never changes 🙂

Your image is upside down. Here it is in correct orientation (north up). The red blob (circled) must be Lunae planum and the dark region next to should be Xanthe terra. You got valles Marineris (circeld on the left) as well!

Looks like you saw Iapetus when it was exactly north of Saturn so in superiour conjunction. I would expect it to be a bit brighter than mag 11.7 at that time, the darkest it gets is 11.9 which is at eastern elongation. Once it moves to the west of Saturn it should be mag 11 or less. Actually there can be a small discrepancy from 2015 to now because of the inclination of the Saturnian moon system. Currently we are seeing it more edge on so the difference of brightness will be more pronounced.

I am observing Saturn tonight, the seeing is excellent and my 120mm SW Mak is pushing x200. I can clearly see Iapetus, it is diagonally opposite to Titan with Saturn in the middle. Dione and Rhea are also visible with averted vision, despite boing much closer to Saturn. Iapetus is famous for being 2 magnitudes brighter when west of Saturn (like tonight, it's about mag 10). East of Saturn it is only mag 12 so not easily seen in small scopes.

Do you have darker skies? Star hopping with a rdf works only when you can see enough stars. I would say you may need to at least see magnitude 4 stars to have sufficiently many to orient yourself. Many people use rdf in combination with a RACI optical finder. The rdf is used first to point roughly in the correct area of sky and then the actual star hopping is done with the optical finder.

The next couple of years will be good for Jupiter observation! Already this one is far better than the previous years.

I have both. From experience the planets need a bit more that x100 times magnification in good conditions, so if you have to choose one I'd go for the 8mm.

Oh yes, sorry, the midnight timing is only around opposition, after that the highest point is reached about 3-4 minutes earler each day. In summary we will have good views of Jupiter earlier and earlier in the evenings, all the way to January, and it will be rising up to 35-40 degrees viewed from the UK.

Yes, the seeing is very good here too. I'm using a 120mm Mak and can see lots of detail on Jupiter and Saturn. Ganymede just got eclipsed. There is some haze which acts as a ND filter on Jupiter.

For each night the max altitude will be near midnight GMT. You can calculate it from the declination of Jupiter for the day by the formula: 90+ (Jupiter declination)-(lattitude of location). Currently Jupiter is moving retrodrade, so its altitude will dip a little for the next month or so, then from the end of November it will start to increase again.

Ideally the sun should be about 10 degrees below the horizon for the eastern sky to be dark enough to spot Mercury. you are right, this week is good: The greatest elongation is 18 degrees this weekend, so Mercury will be nearly 8 degrees up an hour before sunset. I've seen it several times with binoculars, but it is never easy. Check an online program like stellarium.org, it will give you precise alt az coordinates to look at your location at any specific time.

Yes there is: Explore Scientific (the 82 degree line). They are not cheap but considerably cheaper than TV Naglers.

There is a simple way to get the right distance set. At daytime point the binos at a distant target and starting from widest position begin to bring the two barrels together until the two circles merge into one circle. Ignore the view. Once you see just one circle this is the correct ipd distance for you. Ideally the objects you see should also merge into one. If not then the binos need collimation