Opinion on 6 inch ota

[kon1966]

Hi guys
Do more imaging than visual and used to have 8se sct but sold it. And now use ed80 with .8 and .63 reducer to give very wide views on canon eos.

Looking to buy 6 inch either f5 newtonian, rc6 but never used one, or even 6se ota.
Opinion greatly appreciated, mount I have is an avx.

Regards
Kon

[gregbradley]

The Newt will give wider views than a 6 inch RC. I have seen lots of excellent RC images. Usually they were the carbon fibre tubed RC8.

Lots of Newt images around that are superb. You should try to get one with a carbon fibre tube. I think carbon fibre makes a big difference to scopes.

Greg.

[kon1966]

Hi Greg
So is it RC or newtonian in carbon fibre.
Regards
Kon

[glend]

Kon, consider the photographic speed, a Newt is going to be faster than an RC, and this makes imaging easier imho. Sure the RC gives you longer focal length, in exchange for the slower speed but it comes down to what you want to image. I have owned both 8" newts and an 8" RC, and without a doubt the Newt is much easier to live with, and to set and keep collimated. The budget GSO 6" and 8" RCs have a pretty bad reputation for being hard to collimate, keep collimated, and for having tilted focusers. If you do a search on "RC08 collimation" you will get plenty to read on the subject.

[GOTO]

RCs are diabolical, imo, to collimate and the 8s don't have a spot on the secondary. I gave up in the end and sold it. I'd love a 6inch f4 quality Newt.

[kon1966]

Thanks guys,
Going for a 6 inch newtonian back to my first telescope 15 years ago. Back in the day had a 10 inch f5 dob and boy did it suck in the light.
Regards
Kon

[gregbradley]

I think that is a good choice Con. There are lots who are using Newts and there are plenty of stunning images.

Greg.

[Startrek]

Ive used a Bintel GSO 6” f6 newt for imaging with a canon DSLR APS-C crop sensor over the last 3 years in Bortle 8 suburban Sydney and can guarantee it is a great all round scope , easy to collimate , light weight about 6.5 kg and at my image scale and field of view can fit most object , clusters , nebulas and galaxies
I also have an 8” f5 newt for imaging at my weekender ( dark site ) plus a 12” Goto dob for visual

A newt man through and through !!!

[ChrisV]

+1. My refractor is easy to use. But bang for buck - you can't beat a newt, even my gso after fiddling around with it

[kon1966]

Just picked up gso 6 inch f5 newtonian. Missed out on f4 by a day, all sold out. A bit better on coma. Thanks for all your opinions.
Regard
Kon

[luka]

Great choice Kon.



By the way, RC8 do have a center spot on the secondary. I think I read that only the very early ones did not have it.

[kon1966]

Hi guys
Laser collimated and did and followed the usual steps. When I look through the eyepiece, it llooks like the photo attached from astro baby guide for f5 newtonians.

How do I proceed from here.
Regards
Kon

[PaulSthcoast]

Hi everyone,

Just in regards to the Field of View from an RC-8.

Here is a screen shot taken via mobile phone of a
computer screen with an RC-8 I set up for a friend October 2019.

This was the scopes first light.

Image shows PHD2 with Moon in shot, just as an experiment
for him to see how it looked, as the clouds were rolling in.

Main image is via Sharpcap using a ZWO 120MC-2.

There was cloud, as the PHD2 shot shows, but the RC punched through it.

Paul.

[mental4astro]

Kon,

Congrats on your new purchase :thumbsup:

One question about your collimation process - did you ONLY use a laser?

I ask as even if you had used other tools, there might be people reading this who may think that a laser will do it all and it's the only tool you will need.

A laser alone will not allow you to get the secondary mirror set properly.

The Astro Baby page you refer to is excellent because it describes the process needed to FIRST sort out the secondary BEFORE touching the primary mirror.

Get the secondary right from the start, and only then will the final tweeking of the primary will give you your best possible collimation and performance out of your Newt or dob.

I mention this for those people who may not be aware of the pitfalls that lasers alone present in the collimation process. You don't even need a laser to collimate a Newt with either - they are a convenience tool. A Cheshire eyepiece or Auto collimator (that's what the tool is called) is capable of doing it all and star testing will provide the final tweeks.

I too at one time thought a laser did it all. I'd adjust the colli screws on the secondary and then the primary and off I'd go. But slowly over time the "collimated image" was getting worse and highly distorted and no matter what I did was the image improving. Out of desperation one night I thought I'd look down the focuser drawtube and OMG! The secondary mirror was so far out of whack! It was no where properly positioned in front of focuser that it did not take a tool to show this!!! The primary was also out as it had to be adjusted for the misaligned secondary.

That was when the penny dropped for me as to why I wss getting a false-positive collimation from just using the laser.

A laser alone will not get all aspects of the secondary sorted out for you. This includes the optimal position in relation to the focuser and drawtube.

Sorry for the digression, but I don't want to see you, Kon, find yourself in difficulties with your new scope and tear your hair out from frusyration that stems from a fundamental aspect of Newts.

Alex.