Author Topic: Going to a 130mm reflector from a 70mm refractor  (Read 134 times)

Waka Belcher

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Going to a 130mm reflector from a 70mm refractor
« on: December 24, 2017, 08:33:41 AM »
What can I expect from the 5 inch reflector in contrast to my old 70mm refractor?

I mean as in can I see additional deep space objects and much more features on the moon and planets?I thought about that too considering that the 60mm increase in aperture but a person just recently told me a
Refractor will give sharper images than a reflector hence making the 70mm and 130mm the same, is this true?



Trendsetters Branch

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #1 on: December 27, 2017, 09:43:07 PM »
The 130mm reflector will definitely give brighter images and more details than a 70mm refractor. Cool down time for such sized scopes is very short.

Inch per inch nothing beats an apochromatic refractor but I am assuming you have an achromatic refractor. Either way, aperture rules. As long as the reflector is collimated and assuming the mirror is good the 5-in is a good step up.

Why not get an 8-in reflector?

vieproltesro

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #2 on: December 28, 2017, 12:01:31 AM »
Quote
What can I expect from the 5 inch reflector compared to my old 70mm refractor?

I mean as in will I see more deep space objects and more features on the moon and planets?I thought about that too considering the 60mm increase in aperture but someone just recently told me that a
refractor will give sharper images than a reflector thus making the 70mm and 130mm the same, is this true?


If both are of good quality, then you will see a good deal more in the 5 inch reflector. A good quality 5 inch reflector has significantly greater resolving power as well as gathering much more light. You will see more planetary detail, fainter deep sky objects. The assumption here is that the reflector is of good quality and most are but there are some that are compromised by poor optics or a poor design. Which scope are you looking at?

Also, in my experience, commercially available 5 inch reflectors do take some real time to cool down (45 minutes - 60minutes) so they are giving their sharpest, cleanest images.

Jon

alssysenar

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #3 on: December 29, 2017, 04:49:13 AM »
Quote
What can I expect from the 5 inch reflector compared to my old 70mm refractor?

I mean as in will I see more deep space objects and more features on the moon and planets?I thought about that too considering the 60mm increase in aperture but someone just recently told me that a
refractor will give sharper images than a reflector thus making the 70mm and 130mm the same, is this true?

Between those two sizes and types they'd be a range of magnifications in the of middle to possibly middle high that both telescopes could easily handle and for those matching magnifications, assuming good quality of both telescopes, the refractor would deliver the cleaner image. Higher magnification and light gathering is the reward with larger telescopes and while a quality 130mm refractor and mount would cost thousands of dollars, the same size reflector, not top quality but nice enough can be had new for as little as $200.

Ricky Mondal

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #4 on: December 30, 2017, 02:02:12 AM »
I have an 80mm refractor as a guidescope mounted to my 130mm reflector. The refractor is nice, great for finding objects, but it just doesn't quite get to the same level as the reflector

Chris Smale

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #5 on: December 30, 2017, 10:03:48 PM »
I'd say in general the 130mm will be much better overall. However I think we'd probably need the details on both scopes. If it were a 130mm reflector and a 100mm refractor that could be a closer fight.

There are some reflectors that have a poor design (bird jones) which are not recommended. If you see a 130mm with a very short tube and it says it's an F8 or F10 focal ratio that's a bad sign.

I've compared my 103mm apo refractor (a pretty expensive tube) to an Orion XT6 6 inch F8 reflector (150mm). The refractor was a bit sharper but the reflector gathered more light. I personally think it was a pretty close fight with pluses and minuses on both sides. I bought the refractor used for around $1000 just for the tube/rings. The XT6 cost me $250 new (they are around $300 now) for the whole setup.

I'd say in general I prefer refractors in smaller sizes (say2-4 inches), but after that I prefer other designs. Mostly because refractors get long, hard to mount, and expensive in the larger sizes. I may consider a 5 inch refractor some day...but I usually think that money would be better spent on aperture or eyepieces.

If you have the details on the two scopes we could provide better expectations.

Adam Mann

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #6 on: January 04, 2018, 03:23:02 PM »
Well the refractor was a Celestron powerseeker 70AZ which believe it or not showed me some things that I thought weren't possible with such a small scope
The reflector I'm looking at is the Celestron Powerseeker 127EQ, now I know that there are better reflectors out there but I'm short on money right now so I was looking at inexpensive reflectors
I mean I got my refractor for $50 and the reflector is currently $130, surely it should give me clearer and brighter images?
Oh and It was 127mm guys, sorry for saying 130mm, although I don't know if those 3mm will make a significant difference

tissuppgunre

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #7 on: January 08, 2018, 12:17:34 AM »
Oh and the reflector has a focal ratio of: F/8
And a focal lenght of 1000mm

pensranbafarc

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #8 on: January 08, 2018, 05:32:05 AM »
The powerseeker is a Bird-Jones design. I have never used one, so I can't comment on it's quality, but it is a spherical mirror with a built in barlow to get that long focal length. I have read that they are tough to collimate, and have aberration issues from the spherical mirror.

I have nothing but good reviews for the AWB OneSky reflector (130mm f/5) - its a bit more expensive, and doesn't come with an EQ mount, but as a beginner myself it has really opened the door to astronomy for me

ransgesislu

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #9 on: January 08, 2018, 06:09:02 PM »
Avoid the 127mm!

Rahul Sanders

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #10 on: January 09, 2018, 03:50:03 AM »
Yes...those are the scopes to avoid (the 127 powerseeker). In this situation I think I actually would pick the 70mm powerseeker.

Suggest looking into Orion's offerings (www.telescope.com) or looking on the used market.

It's hard to suggest many scopes in the sub $150 range. A 70mm refractor is a good choice in that range.

The powerseeker 114 may be slightly better but I fear the mount won't handle that tube very well.

You may be able to find a used Orion XT6 or XT8 dobsonianfor around $200. That would be a great scope (had one of the XT6smyself). Brand new they are $300...so maybe a bit out of range. Those are much more capable scopes and would be a good complement to your 70mm refractor.

chionewssesu

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #11 on: January 10, 2018, 12:10:44 AM »
Quote
someone just recently told me that a refractor will give sharper images than a reflector thus making the 70mm and 130mm the same, is this true?


No, 70mm and 130mm views will not be the same, unless the optics in the 130 are poor. My thought on this is that if you can afford it, keep the 70mm refractor and get a 400mm or larger Dob. In other words, expand your reflector capacity; your 70mm would be a nice complement to your reflector.

Paul Syring

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #12 on: January 10, 2018, 06:32:25 AM »
Quote
Quote

someone just recently told me that a refractor will give sharper images than a reflector thus making the 70mm and 130mm the same, is this true?


My thought on this is that if you can afford it, keep the 70mm refractor and get a 400mm or larger Dob. In other words, expand your reflector capacity; your 70mm would be a nice complement to your reflector.
If I owned a 400mm plus scope, I'd use the 70mm to beat off any varmits in my backyard! .
Sam

noneanoncrag

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #13 on: January 10, 2018, 09:02:06 AM »
The 70mm has my vote over the birdy and over the 400mm, just to big for me,
Hey my 250mm doesn't get out much for the same reason, you can find a
Nice 150mm f5 or f8 used with no problem. I've seen 130's cheap and if you
Want to play with a newt while you save for bigger you can pick up a 114mm
Dirt cheap, don't laugh, other then the cheap focusers, they aint bad at all.
I picked up a 4" carton f6 mirror here on CN, cut the tube on a 114mm, replaced
The focuser with a crayford, mounted a 8x50mm finder, mounted it on a polaris
Mount, nice little grab and go and a fun project. Your options are limitless, just
Have fun.

Robert Johnson

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Re: Going to a 130mm reflector from a 70mm refractor
« Reply #14 on: January 10, 2018, 09:01:17 PM »
Quote
Well the refractor was a Celestron powerseeker 70AZ which believe it or not showed me some things that I thought weren't possible with such a small scopeThe reflector I'm looking at is the Celestron Powerseeker 127EQ, now I know that there are better reflectors out there but I'm short on money right now so I was looking at inexpensive reflectorsI mean I got my refractor for $50 and the reflector is currently $130, surely it should give me clearer and brighter images?Oh and It was 127mm guys, sorry for saying 130mm, although I don't know if those 3mm will make a significant difference
stay away from the 127 reflector, i'd rather see you get the 114 powerseeker. there is a short tube 130mm orion in the clearance section for 237 complete.