Refractor vs SCT

[MjrTom]

Thanks Shane,

I always sit to observe. Over the last couple of years I have realised I see a lot more when seated. I can control my breathing and position my eye in the prime spot of the eyepiece light cone a lot easier. (plus its a lot easier on my neck/back!)

I use the drift & nudge method as well.

I was using my Equinox 80 on the moon last night at 200x magnification also using the 3-6mm Nagler (& 2.5x powermate) and still observe fine without tracking.

If anything I find these Alt/Az mounts are far smoother than any mass produced dobs I have used in the past.

The physical mass of a Dob is quite a handful!

[michael.h.f.wilkinson]

One thing I found troublesome when handling Olly's 20" dob was finding things near zenith (always an issue with alt-az in my experience). EQ mounts have similar problems with the area around the pole (which I only visit for the odd supernova and Caldwell 1). I personally have found that star-hopping based on motion in RA and DEC translates more easily from my Sky Atlas. EQ mounts do take some getting used to, and they are more expensive, but once you get used to them, they are great.

[MjrTom]

Thanks Michael

Yes that is one thing I do find annoying. A big downside of alt/az mounts is looking for stuff around the Zenith.

The bearings have to be very smooth otherwise you are fighting like made to work out which axis needs to be adjusted to keep on target.

I tend not to use a standard sky atlas and use a smart phone app and old fashioned star hopping to find stuff.

Coordinates dont mean a lot to me.

[michael.h.f.wilkinson]

Thanks Michael

Yes that is one thing I do find annoying. A big downside of alt/az mounts is looking for stuff around the Zenith.

The bearings have to be very smooth otherwise you are fighting like made to work out which axis needs to be adjusted to keep on target.

I tend not to use a standard sky atlas and use a smart phone app and old fashioned star hopping to find stuff.

Coordinates dont mean a lot to me.

I use old fashioned star hopping too, but at a 37 deg angle

[great_bear]

I think the moon is a special case; It's very enjoyable to watch it drift across the view at high mag...

[Moonshane]

yeah I agree with this although it's more the positioning with the Telrad that's tricky rather than the observing once in position.

[MjrTom]

Yeah sometimes you have to be contorted into some weird positions when trying to sight a Telrad. I use an RDF mounted on a riser which although does not have the circles does give you a little bit more space to manoeuvre

I agree that the moon is one of those targets which watching it drift across the view is nice, also I think globular clusters and the planets fall into this bracket as well.

Looking at Jupiter drift across a wide field of view gives a great sence of the speed in which the celestial object moves at

[MjrTom]

I managed to test out the Tele-OPtic (Berlebach) GIRO III Alt/Az mount last night and oh boy its a beauty!

Super smooth in both axis and once adjusted so both axis are equal tension it is amazing, being able to just trawl through the milkyway with no effot is sublime.

This should be a perfect mount for a much larger OTA

[michael.h.f.wilkinson]

Sounds interesting. I am considering getting a Mini Giro for my 80mm. Sounds like these mounts are well made.

[great_bear]

With a much larger OTA however, you're going to need counterweights.

I feel that once an AltAz mount starts requiring counterweights it's game over for me, since the advantages over an equatorial mount start to evaporate.

[Moonshane]

or another scope

[MjrTom]

Sounds interesting. I am considering getting a Mini Giro for my 80mm. Sounds like these mounts are well made.

So was I, in the end when this Giro III came up for sale at similar money to the Mini Giro I jumped at the chance.

The Giro III is quite a bit bigger than the Mini Giro. Not something I had really appreciated to be honest. More like a skywatcher Sky-Tee2

With a much larger OTA however, you're going to need counterweights.

I feel that once an AltAz mount starts requiring counterweights it's game over for me, since the advantages over an equatorial mount start to evaporate.

or another scope

Thanks guys!

Shane has answered my question.

The C8 @ ~6kg will be balanced with my ED80 @ 3.5kg

Thats ~10Kg of OTA's which is half the load capacity of the tripod and mount which are both rated to ~20kg.

A nice touch I noted with this mount is you could adjust the position of the individual dovetail clamps on the shared axle/spindle. This means that I could spot something with the refractor and then switch over to the SCT for a high power and brighter view of what I found. Obviously once I had aligned the two scopes to eachother.

[michael.h.f.wilkinson]

I like the low weight of the mini giro, it means I can take on a plane more easily.

[michael.h.f.wilkinson]

BTW you can really use the ED as a monster finder in this set up. Bigger even than my 16x70 finder.

[MjrTom]

I like the low weight of the mini giro, it means I can take on a plane more easily.

Yeah that is worth considering. I dont think I would fly with this mount but the Mini Giro would be perfect for this> If I remember correctly its less than half the weight

BTW you can really use the ED as a monster finder in this set up. Bigger even than my 16x70 finder.

Yeah thats what I was thinking, miles better light gathering ability than using a 9x50 finderscope.

Thats a pretty impressive finderscope that you use

[great_bear]

I was seriously thinking of snapping up Bender's GiroIII - glad it went to a good home

[MjrTom]

I was seriously thinking of snapping up Bender's GiroIII - glad it went to a good home

Thanks

I got it for a good price and since it is my main mount is going to get some regular use

Its a beast! Its like a battle axe when mounted on my heavy tripod, takes a bit of lifting on its own!