i'm very tempted

[Andywilliams]

Hi all,

Having read a fair bit of this thread and also being impressed by the quality of the images, I am very tempted to buy a 130 PDS and give it a crack !

A couple of questions though and I apologise in advance if these have already been asked ad nauseam.

I have enough money to invest in a HEQ5 pro. I also have enough to put my first steps into mono ccd imaging.

I don't have enough left over for the recommended 80mm esprit, so I thought I might have a go with this impressive scope.

1) I will need to saw off the focussing tube from the get go ? I find this a little bit scary.

2) do you need to do the sawing if you buy a 150 PDS?

3) this scope vs a 6 inch RC? any major differences? the thing putting me off the 6 inch RC is the reduced FOV. Is this necessarily an unsurmountable issue?

4) can you please recommend a ccd mono camera that will not under/over sample with this particular set up?

So many questions !!

Thankyou one and all and clear skies !

Andy

 

[alan potts]

I would say that the 6 inch RCwhich I have owned in the past was beyond the mounts and many peoples ability to guide, mine for sure, it has been done but by people that know what they are doing It is a slowish F 9 scope and has a F/L of 1320mm I think, you can buy focal reducers but this is all extra cost. I was always advised to keep below 1000mm F/L, there may well be some that would say this is too high to start out with. This is one of the reasons why 80mm refractors are quoted with F/L around the 500mm mark, I don't see why it has to be a Espirit, many use the ED version and produce fine results.

Alan

[jimjam11]

58 minutes ago, alan potts said:

I would say that the 6 inch RCwhich I have owned in the past was beyond the mounts and many peoples ability to guide, mine for sure, it has been done but by people that know what they are doing It is a slowish F 9 scope and has a F/L of 1320mm I think, you can buy focal reducers but this is all extra cost. I was always advised to keep below 1000mm F/L, there may well be some that would say this is too high to start out with. This is one of the reasons why 80mm refractors are quoted with F/L around the 500mm mark, I don't see why it has to be a Espirit, many use the ED version and produce fine results.

Alan

And the demand/need for long focal lengths to reach optimal sampling is diminishing as pixels get smaller in newer cameras. An rc6 paired with 3.8micron pixels gets you < 0.5" per pixel which makes guiding even more demanding and exceeds seeing in almost all conditions leading to oversampling. 

[rickwayne]

The classic advice is to go long on the mount, shorting the scope if you have to. That sounds insane, but it's really not. And a wide-field refractor is the lightest, smallest, most forgiving optic to start with. There is plenty to learn even in the shallow end of the pool, and while some people manage to tie bricks to their feet, jump into the deep end, and still swim successfully, it's a low-percentage business.

80mm is the most-often-recommended aperture, but less expensive options are still perfectly viable. I work with a 70mm Stellarvue and am by no means limited by my optics! (Translation: I still have a lot to learn.) Heck, get the best mount you can afford and pick up an old Pentax M42 telephoto and a Canon adapter. You will be awhile outgrowing even that!