Is it important?

[Zul]

Hello.

I'am thinking to get new OTA for visual astronomy. And i want to ask is it important to have 1:10 dual speed crayford focuser for visual astronomy? Can't decide witch to grab 130/650 newton with dual speed crayford or 150/750 newton with crayford but one speed? My mount is Eq3. Thanks for answers!

[DirkSteele]

I am sure you will find two camps of people with views on this subject on SGL. I am lucky enough to have 1:10 focusers on all my scopes and find them invaluable when achieving fine focus visually, so for me I would always perfer to have them. And yet I have used telescopes without this feature that have very well made focusers and they have performed very well also.

[Keiran]

If it is purely for visual, it is not really needed. You only need the fine focus for Imaging really, where you are using a computer or screen to focus, and yopu need the focus spot on.

[carlc]

Personally: Take the aperture and upgrade the focuser later.

I imagine dual speed is nice (and has benefits) but the aperture would be of greater benefit to you.

[John]

I have both types of focuser on my scopes. Dual speed is useful on faster scopes (say F/7 or faster) as the point of focus is more critical but I still manage to get sharp focus with my 10" F/4.8 newtonian and thats got a single speed focuser. Having a focuser with little or no "play" or backlash and a nice smooth motion is really essential though so it's worth tuning a single speed to get that.

[E621Keith]

Hello.

I'am thinking to get new OTA for visual astronomy. And i want to ask is it important to have 1:10 dual speed crayford focuser for visual astronomy? Can't decide witch to grab 130/650 newton with dual speed crayford or 150/750 newton with crayford but one speed? My mount is Eq3. Thanks for answers!

1 in 10 focuser isn't necessary for visual, but it's nice to have it. You eyes can fine tune small focus errors. An alternative is to fit a large diameter focus wheel to the focuser knob.

As for Crayford .... let say there are good ones and bad ones. Feathertouch and Moonlite crayfords are great, but I'd rather have a standard R&P focuser than a William optics DDG.

[RikM]

I would go for more aperture over a dual speed focuser as well.

[Zul]

Thanks for such a fast replys! I would go for 150/750 with dual speed but budged isin't letting me . And for now i want more aperture. So i would go for one speed at the moment maybe someday i will upgrade it.

[E621Keith]

Go for the larger scope. You can always upgrade the focuser at a later date

[ollypenrice]

Personally I rarely touch the slow motion focus knobs in visual observing. I live by them when imaging, of course.

Olly

[Carbon]

Although it is not necessary, once you have it you'll never want to go back to a single speed.

I recently converted my single speed crayford using a dual speed conversion kit for that focuser.

[OzDave]

The other thing you can do with a single speed focuser us attach a larger diameter disc to the existing knob and turn the disc instead. It won't be as nice as a 10x knob, but it will help a bit and doesn't cost anything. E.g use a jam jar lid

Sent from my iPhone using Tapatalk

[Zul]

Hello.

Have a new question. I have Eq3-2 mount witch weight limit is 7kg. Will it be very bad for visual astronomy with 9kg telescope on it?

[E621Keith]

It won't break if that's what you are asking. However, it will be so wobbly that it will become unusable. I've seen a 150p on a EQ3-2 and it's about the biggest scope I'd want to put on that mount. Don't try to put a 200p on it.

[Rossco72]

For me if its for visual then get the larger aperture and you will benefit more from the extra light grasp

Just my 2p worth

Sent from my Nexus 7 using Tapatalk 2

[alan potts]

I would say no it is not important to have one of these.

I bought a Baader focuser for my LX 200, just could get used to the other focuser. Now I have removed it from the scope and never use it, waste of money for me. However on faster F No's the area of focus or sweet spot as it is offen called is much smaller, so then it would be nice to have. I do not think it is vital though, not for visual.

Alan

[RikM]

I used a 150P on an EQ3-2 for a couple of years and it's fine for visual use. Where do you get the 9kg from though? Are you thinking about a TAL 150P? The SkyWatcher is only a smidge over 6kg with rings, dovetail, finder, and a nice big EP.

[Zul]

One man in my local forum sells GSO 200/1000 with dual speed creyford and it weights 9kgs.And its price is same as new 150/750 with one speed creyford.

[E621Keith]

9 kg is close to the maximum capacity of a EQ5 and it will be too much for your eq3-2. There is no point getting a big telescope if your mount isn't up to the job.

[Naemeth]

I wouldn't even dare to stretch the stated payload even for visual. After all, you wouldn't stretch the weight limit of an elevator would you? Same principle...

Either get the smaller 150P or it will have to be the 200P with a bigger mount.

[Zul]

Okay thanks for replys!

[E621Keith]

I wouldn't even dare to stretch the stated payload even for visual. After all, you wouldn't stretch the weight limit of an elevator would you? Same principle...

Either get the smaller 150P or it will have to be the 200P with a bigger mount.

I'd say Skywatcher's stated payload capacity are already stretched. When you look at the value stated by Vixen for the original GP, it was only rated to carry 5kg, yet SW the rated the EQ5 (clone of GP) for 9kg.

[Naemeth]

I'd say Skywatcher's stated payload capacity are already stretched. When you look at the value stated by Vixen for the original GP, it was only rated to carry 5kg, yet SW the rated the EQ5 (clone of GP) for 9kg.

For visual, the stretching of payload to some extent is alright, but for imaging, the accepted rule is half of the stated payload. Which may be much nearer the actual payload.

[Moonshane]

I have dual speeds on all my scopes and would not be without them but a well adjusted single speed will work very well indeed also.

if you are not looking to do an AP (and undermounting an OTA is no way to go about it if you were) then a dobsonian base in my view is the most stable, ergonomic and easy to deal with mount available. you could either make one or buy one but it's the way I'd go. I generally agree with more aperture over gadgets.