Dob vs EQ3 for a Beginner

[Omega]

Hi All,

I'm in my final phase of research before I opt for my first scope and would be most grateful for any advice again. Everyone has been most helpful here so far, feel fortunate to have found a forum with such knowledgeable and friendly people.

My initial requirement was for a scope that covered both DSLR astrophotography and optical bases, but the further I delve into research of DSLR astrophotography the more I realise that it appears to be something I should endeavour once a solid understanding of sky and optics have been established.

So now my requirement is purely visual. I'm looking at a Skywatcher 150P EQ3 or the Skyliner 200P Dob. With the Dob I can afford more aperture, but will I be able to locate targets as easily? Would a 200P Dob be transportable in the back of a hatchback car? Would it be worth paying that little extra for the Flextube AUTO version for tracking?

I'm interested mainly in planetary and DSO, will the views through a 200P be that much more impressive for both than the 150P?

Thanks guys/girls

[Bizibilder]

For portability and ease of use (plonk it down and off you go!) the Dob wins hands down. The greater aparture will give better views of DSO's. The Dob will also give almost double the magnification (with the provided eyepieces) for the planets and Moon - but remember in Astro magnification is not always important.

To be honest the EQ3 is not up to serious astrophotography so you are better off putting your money into aparture.

PS You can eventually mount the "tube" Dob on a decent equatorial mount - you will just need to buy tube rings and a dovetail bar to suit. The truss tube Dobs are not that easy to convert onto another mount.

[onesmallstep]

Hi and welcome to SGL

As you can see from my sig I'm rooting for the 200P. Not only do you get more observing bang for your buck the Dob design means it will be more straightforward to use as you only have the AltAz (altitude azimuth) directions to concentrate on. EQ mounts have to be aligned to Polaris to be used efficiently and can be complicated for less experienced astronomers.

As for locating objects either download Stellarium freeware onto your computer or invest in a decent starguide, several titles available but my own is the Sky & Telescope Pocket Sky Atlas bought from Amazon for under a tenner.

HTH!

[brantuk]

You'll definitely get better views in the larger aperture scope. Good idea to put imaging on hold - it's a tricky subject and highly technical. THe dob will fit in your hatchback easily with the tube across the back seat and mount in the boot.

Locating targets will be more dependent on a knowledge of the sky - I found the center pages of Sky at Night and Astornomy Now were superb when I first started. If you still have trouble then a Wixey angle guage and azimuth setting circle will make a superb pointing system for around £30.

The flextubes are very nice and the auto tracking is very useful - you don't have to nudge so much with 16"+ apertures but at 8" my personal preference would be for auto. But you will also need a shroud to block stray light.

You will need a collimating tool - pretty much essential with a Newtonian scope - hope that helps

[fbassett]

I have the explorer 150p on an EQ3 mount and after only 4 or 5 observing sessions decided the EQ3 was to wobbly for my liking so I got myself a CG5. I have never used a dob but I would think it would be more stable than the EQ3.

[Omega]

Ahh i see, so the Flextube would not be as flexible in terms of future use. So is there actually any benefit to the Flextube system? Am I right in thinking you can in effect adjust the focal ratio?

[Bizibilder]

The Flextube simply collapses for transport. It does not allow you to vary the focal ratio - the mirrors are of fixed focal length. (Although the idea of a "Zoom" scope sounds interesting!! )

[John]

You can't adjust the focal ratio with the Flextube. It's advantage is that the tube can be made much shorter for storage. It needs to be fully extended for use.

Of the 2 options you are looking at I'd go for the 8" dobsonian. Light is a precious resource in astronomy and extra aperture is the only way to maximise it.

[onesmallstep]

The flextube system is designed primarily for weight and size reduction and for ease of storage and transport. Given the parabolixc curvature of the mirror the flextube has to be extended to its fullest extent to be used at the designated focal length. Not that I've tried but shortening the tube length would also shorten the focal length and render the scope unusable for effective observing.

NB, If any SGLers have successfully tried this please correct me.

HTH!

[Moonshane]

I believe the flextubes are heavier than their solid tube 'brothers'?

[brantuk]

For future use the flextube auto will facilitate imaging of planets and moon with a webcam. But long exposure photography of deep sky objects on any alt az mount will be extremely limited. It's nice to track automatically though - especially with apertures under 12" (imho).

The only way to change the effective focal length is through cunning use of eyepieces and barlows lol. The struts are just for transport and storage as John says

[onesmallstep]

The flextube system is designed primarily for weight and size reduction and for ease of storage and transport. Given the parabolixc curvature of the mirror the flextube has to be extended to its fullest extent to be used at the designated focal length. Not that I've tried but shortening the tube length would also shorten the focal length and render the scope unusable for effective observing.

NB, If any SGLers have successfully tried this please correct me.

HTH!

Oops! Just noticed a VERY unintentional typo error in my previous post. No prizes for finding it but please feel welcome to have a laugh at my expense.

[Omega]

The flextubes are very nice and the auto tracking is very useful - you don't have to nudge so much with 16"+ apertures but at 8" my personal preference would be for auto. But you will also need a shroud to block stray light.

You will need a collimating tool - pretty much essential with a Newtonian scope - hope that helps

This is one of things that puzzles me, when the Flextube is extended for observing, doesn't the empty/exposed mid make it vulnerable to unintended LP? Are there official shades/shrouds available from Skywatcher?

[Pug]

Almost a Father Ted moment!

[onesmallstep]

Yes, you can buy light shrouds to enclose the open part of the tube.

[Omega]

Thanks, I found the Astrozap shroud which looks very tidy.

Am I likely to need any other accessories or additional eye pieces/filters for immediate planetary observing?

[onesmallstep]

A set of planetary filters which would also include a moon filter as advised above.

A 2x Barlow lens to use with existing EPs to increase the magnification.

A collimation tool to help tweak the optics and keep your scope in tip-top condition.

Check out astro suppliers including site sponsors FLO above.

[John]

Most people will upgrade the supplied eyepieces in due course but it's best to wait until you have used the scope for a bit as the choice is so vast !

You want a red torch, a collimator device like a cheshire eyepiece and a good guide to the night sky. A red dot type finder like a Telrad or a Rigel Quikfinder is also very useful on dobs I feel.

Sorry to contradict the previous poster but I really would not rush into any filters - apart from nebulae filters I've never used any in 30 years in the hobby, including moon filters.

[Omega]

Thanks for all the valuable advice. So it seems a collimator tool is essential and also a guide of the sky. Would anyone recommend the Celestron Sky Scout as an alternative to PC software? Are they accurate and practical?

[onesmallstep]

The SkyScout is a useful tool and Celestron had a 90mm refractor model made from non-ferrous materials so that it could be used with the SkyScout as a push-to scope. If you use Stellarium alongside a printed starguide you should be OK as you can compare the starguide views with the Stellarium virtual sky as a learning tool.

[peterules]

Eq all the way for me

[mcro89]

I got myself the 150p a little while back and its great. For getting into astrophotography its good to learn the basics with because it has the equatorial and if you get some motors on it you can do some ok long exposures.

Everyone on here seems to be a bit negative about first time buyers and astrophotography but i think getting a 150p is great to start playing around with astrophotography and also for learning the sky. Planets are a good view as well and yes the tripod is meant to be wobbly but i haven't anything to compare it to and i think it will do for now, for learning, and i can upgrade it in a year or so.

I always got the impression that dobs are a bit harder to get longer exposure photos unless you get all the high tech expensive stuff.

Oh yea and stuff like polar aligning isn't as hard as some make it to be, takes a few minuets to set everything up but then your away.

Hope this helps

Matt

[BAZ Senior]

I don't think people are being negative, but letting you know from their bitter experience, the pit falls of what to expect. No one on this forum would want to put you off, but would want you to avoid any disappointment.

For what it's worth, the 200p would be a great scope to start out with, I suspect it's probably the most popular scope on here. If when your budget allows, get the gear for imaging, you will know where to look for objects.

[Bizibilder]

You could use a webcam on a Dob to take short (30-60 sec) video's of the Moon and Planets (Jupiter & Saturn) and stack them in Registax. This is a relatively easy start to set you on the path to Astrophotography.

[Omega]

The Skywatcher official site shows a SYNSCAN version of the Skyliner Flextube 200P. I can't seem to find a retailer that offers it though Is it possibly to upgrade the AUTO version to SYNSCAN, does anybody know?

Forgive the elementary nature of the question, but will the AUTO literally adequately track an object once I have it in my sights?