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Advice about telescope


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I went into my local Jessops store today,and they had a Ce!estron

PS telescope for sale at a reduced price of 160 pounds.

The staff did not seem to know much about it,but they called up the information on their computer. Apparently it is a 127 mms reflector with a focal length of 1000 mm. However the telescope length was only about 600 mm.?

Is this worth buying or is there a problem with it.?

Thanks for any advice.

Chris P

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Bird and Jones designed a telescope that uses a spherical primary mirror (easy and cheap to make) together with a lens group that corrects for the image flaws that are caused by spherical mirrors. The corrector also doubles the focal length of the mirror. The BIG drawback of this design is that it is very difficult to keep the optics in properly aligned (collimated). 

A Newtonian telescope uses a parabolic primary mirror. This has no spherical aberration, but is slightly more expensive to make. The Newtonian design does not need a corrector like that in the Bird-Jones design. Newtonians are easy to collimate and can perform very well.

A Dobsonian like Paul recommends is a Newtonian telescope on a simple, effective mount that was made popular by Dobson. This mount keeps the telescope stable and affordable.

The telescope Paul recommends is about the best starter scope you could get:

  • f/8 is better than f/5. f/8 makes the telescope 'easy on the eyepiece'. Most eyepiece designs handle f/8 quite well, while quite a few eyepieces don't work that well in an f/5. f/8 also causes less curvature of the focal plane. Coma, which is an image aberration from parabolic mirrors, is much less obvious in f/8 than in f/5.
  • 6" f/8 works really well on the Moon and planets.
  • 6" aperture is big enough for some deep sky targets like nebulae and galaxies.
  • The Dobsonian mount is well suited for visual observation. 
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2 hours ago, xvariablestarx said:

Run away! its a Powerseeker 127 eq, which is a Bird-Jones scope with bad optical quality.

 

They are also a PITA to collimate. 

Go with FLO and get the one mentioned by @paul mc c. They're base is in your area.

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Thanks for all your comments and advice. I always like the idea of a 150mms Dobsonian reflector, but feel that it would be to long and bulky for me to manage ( I am 70 years old.)

Also I have no practical skills so if the mirrors went out of collimation, I would have no idea how to correct them.

I am interested in observing the moon, planets, double and variable stars, and the brighter deep sky objects, as my  back garden has quite a bit of light pollution.

So a fairly short refractor would be ideal. Any suggestions ?

Also I will give the Celestron 

PS 1000 a miss. Does this mean that all Celestro n

Telescopes are of poor optical quality.?

thanks again

Chris  P

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1 hour ago, devdusty said:

Thanks for all your comments and advice. I always like the idea of a 150mms Dobsonian reflector, but feel that it would be to long and bulky for me to manage ( I am 70 years old.)

Also I have no practical skills so if the mirrors went out of collimation, I would have no idea how to correct them.

I am interested in observing the moon, planets, double and variable stars, and the brighter deep sky objects, as my  back garden has quite a bit of light pollution.

So a fairly short refractor would be ideal. Any suggestions ?

Also I will give the Celestron 

PS 1000 a miss. Does this mean that all Celestro n

Telescopes are of poor optical quality.?

thanks again

Chris  P

Chris

 

Cannot go past either a 200mm or 250mm collapsible Skywatcher dob

I am same age as you, and find if easy to move and set-up, and out a couple times per month also with my astronomy club, doing presentations for primary schools, and Space Badge, Joey's, scout  movement

Had for over 10 years now, and given me faithful service

If only home use, then very much doubt will need to collimate, very often

I use a laser collimator,  which is quick and simple to use

I have a 250mm dob

Pic taken recent public display with my club, with 200mm collapsible in background, with shroud

John

 

Skywatcher 10 inch Dobson.jpg

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7 hours ago, devdusty said:

 Does this mean that all Celestron Telescopes are of poor optical quality.?

Hi Chris. Good to see that you asked about a purchase before committing to a duffer! :)

Not at all is the answer to your question above,  I have won compeitions with mine, but the old adage proves true, you get what you pay for.

For the list of objects you would like to view, perhaps a small SCT telescope on a GOTO alt/az mount might be just right for you?

Like this one

https://www.firstlightoptics.com/se-series/celestron-nexstar-6se.html

Hppy hunting :)

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16 hours ago, cletrac1922 said:

Does this mean that all Celestro n

Telescopes are of poor optical quality.?

Hi Chris, no it does not, you just have to go careful what you buy.  If you are interested, the site sponsors, FLO, do good deals and give great honest advice. 

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A refractor would be a sensible  buy for you Chris. An ed80 would be great for many types of stellar targets.  The problem is you would need a tripod and a mount for it too. The mount.ne only be an Alt Azimuth type, as I guess you just intend casual skirmishes around the night skies.   The telescope is an Apochromatic, which makes them more expensive than it's poor relation the simple Achromat. The Apo version is designed to eliminate false colours.  

Well corrected Newtonians give you true colours too, but you seem reluctant to go for that type in view of the possibility of regular adjustments that may be required.   I suggest you visit some sites that deal in used Astro equipment, Astro Buy Sell UK for example.   You could get a bargain, people are always upgrading their astro gear, and use money from selling their cutrent gear to help finance the upgrade.       Word of warning though,. Be very careful before committing to anything, if you have any doubts, voice your concerns here, and you will get help on how to proceed before risking your money.                           Good luck.

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You may consider a good pair of Binocs.  I have 2 and they booth give excellent views of the moon and the likes of the Pleiades 

They are a 10 X 40 ( made by charles Frank in Glasgow years ago and no longer exist , but any good binocs should be fine ),......and a Celestron 20 x 80......you would probably need a good tripod for the latter, but the tripod I use for my camera works so didnt have to go out and buy a special one.   Most of the time though I can get steady views by holding them right at the end and then leaning the eyepieces against my eyes to take the weight.....and that works fine.   Im 66 so not a youngster.   Best of luck in your search

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Thanks for all your advice. Unfortunately my budget for a telescope is about 150 pounds up to a maximum of 200 pounds. Any suggestions for a reasonable telescope at this price would be welcome.

I saw your comments about binoculars sandycorgi44. I do have a nice pair of 8x40, and I can see fainter stars but I can't keep them steady enough.

the stars are dancing all over the place.!

thanks again

ChrisP

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We've come full circle!

At least you didn't end up with that Bird-Jones thing. 

Even the Dob that was mentioned is £209. That includes the mount. The tube weighs under 6 kg. The base has a carry handle.

Mounted, the Bresser 102 should be around 50% over your budget.

Here's a new dob idea:  a 5" on a tabletop mount for £178  https://www.bresseruk.com/astronomy/bresser-messier-5-dobsonian-telescope.html, if you have a strong wobble-free table to put it on. I'm not sure if tabletop mounts are any good in practice. 

Here's the size of a 6" f/8 compared to a man. The tabletop in the image is probably a 3".

For the targets you have in mind 6" or more would be best, but 5" might do. 

Image result for size  of dobsonian telescopeimage from astronomytrek.com

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2 hours ago, devdusty said:

my budget for a telescope is about 150 pounds up to a maximum of 200 pounds

I assume that includes mount / tripod right?  This probably limits you to a list of achromatic refractors, few Newtonians /dobsonian or a 90mm mak. 

The refractor will show up some chromatic aberration (isn't really an issue). Newtonians / dobsonian are the cheapest per aperature but they more designed for wider field, which from what I saw you perfer to see moon and planets. Mak won't have  chromatic aberration and good for small objects but the limited power due to central obstruction may lessen the details onplanetary bodies.

You also need to consider eyepiece as well.  The usual stock 10mm and 25mm supplied will do its basic job but may need to upgrade at some point. A x2 Barlow is a good place to start as it turns your eyepieces into 5mm and 12.5mm, doubling your range but it will push it's overall cost up (£25 for a skywatcher one).

 

I am fairly new myself so please be aware, but as you asked for a suggestion I say maybe give the astromaster a go if no one else objects? https://www.firstlightoptics.com/celestron-astromaster-series/celestron-astromaster-102az.html

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7 hours ago, Special K said:

I’d go second hand as well so you can get as much value for money as possible. 

Absolutely! I picked up a barely used 10" dob for 200 quid. They are always coming up so worth waiting. The 10" is a pleasure to move and use.

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The heritage 130p is within budget and is capable and easy to move. Can be used on a table or upturned bucket or from the floor or even taken off the base and used on a tripod.

I've seen a Jupiter moon shadow transit when using mine. Tiny bit without question was a shadow transit. 

This one

Heritage 130p

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As the site sponsor, First Light Optics is based in Exeter (and so are you), I suggest a trip to visit them and see what you can get for £200.

They regularly get returns (as they do a 30 day no quibble guarantee) so you could leave your phone number and get them to call you if a nice 100mm (ish) refractor on an Alt-Azimuth (called AZ) mount comes in. Please do avoid Equatorial (called EQ) mount if you want to save your back and neck!

- something like this StarTravel102 on AZ5 mount would be great

https://www.firstlightoptics.com/sky-watcher-az5-deluxe/sky-watcher-startravel-102-az5-deluxe.html

 

Telescope Manufacturers also do SALES PROMOS every now and then so just keep your eyes open on the FLO offers page or the two sponsors forums on this website.

https://stargazerslounge.com/forum/20-sponsor-announcements-and-offers/

https://stargazerslounge.com/forum/197-flo-clearance-offers/

 

As said above do a daily check of astrobuysell for second hand coming up in your area.

http://www.astrobuysell.com/uk/

 

Patience is probably key to getting a great scope for a meagre £200 but it can be done.

Keep posting here and we will do our best to help.

Alan

P.S. I know you said that you did not want a reflector but the best scopes for your budget are reflectors. Have a search on this forum for "skywatcher heritage 130p flextube". 

- you will find plenty of user reviews and photos

- visit FLO and check them out!

https://www.firstlightoptics.com/beginner-telescopes/skywatcher-heritage-130p-flextube.html

- a 6" dobsonian is unbeatable for £209

https://www.firstlightoptics.com/beginner-telescopes/skywatcher-skyliner-150p-dobsonian.html

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