9 replies to this topic

[Elfbob]

Not sure if this an appropriate place for this question, it may be more suitable in the beginners forum. But, nonetheless; I’m going to get started here in visual astronomy. I’m strongly leaning towards getting a Mak-Cassegrain. Probably only 90 or 102mm. I want something really portable and I plan on looking at planets/the moon much more than stars or other deep space objects. With the Mak, I know it helps out a lot to pick up on the details of the planets with the contrast and long focal length, and the speed isn’t as important. What I’m still torn about is the eyepieces. The included eyepieces will be quickly upgraded and I’m not sure if I want to get a set, or pick and choose the lengths that I would like best (still have no idea what those lengths would be). With all this taken into consideration, I’m thinking the easiest and safest choice would be to get a zoom eyepiece. I’ve looked at Celestron’s and Meade’s, but I’m thinking if I’m getting one eyepiece to take the place of 4 or 5, then it makes since to fork over more for something like Orion’s Pro Lanthanum Zoom or Baader’s Mark IV. The Orion is nice but I think it would still be a notch lower than the Baader, and the “Lanthanum” isn’t as advantageous on the Mak vs. other types of scopes. I’m thinking the zoom at 8mm would be very sufficient for planetary viewing at over 160x magnification with a 1300mm focal length, I don’t think a Barlow would be necessary and 320x is not practical in most situations, not to mention its one more obstruction to the light. Thoughts anyone? I know similar discussions have been brought up on other threads, but I feel like I’m coming from a much less experienced side and no one (that I could find) had anything to say about Orion’s newest zoom EP.

Also, I do plan on going to a Star-Party or similar event before buying anything.

[Mitrovarr]

My thoughts:

If this is all you're going to buy for a long time, get a cheaper zoom if it'll allow you to buy a larger Maksutov. They're all starved for aperture, any improvement is a bigger deal than a better eyepiece. Reports indicate the celestron zoom is ok if not as good as the Baader.

If you think you're going to eventually end up with a whole equipment collection like many of us here, get the Baader zoom because it is likely to remain useful even when you have a full eyepiece kit in the future.

Also, either way, you'll also need a low power wide field eyepiece, like a 32mm plossl or 24mm 68 degree field eyepiece.

[SeattleScott]

The Baader has a wider view but not a big deal if you are mostly looking at planets on a tracking mount. The Baader will have less edge distortion, but the Celestron should have very little edge distortion in a Mak anyway. The Lanthanum in the Orion isn’t relevant to what scope it is used with. For all I know the Baader could use Lanthanum also. I have only looked through the Baader and it was quite good.

Scott

[sg6]

Will ask about the scope choice - why?

If reason is Planets and Moon you have 3 planets and 1 moon. Choice is limited. Also consider Mars is next to the sun at present and achieves a good position to us in October 2020.

 

Mak/SCT will produce a relatively narrow field so makes things a bit more difficult. At 90mm the focal length is around 1250 so with a 30mm Plossl that delivers 42x so around a 1 degree field at the widest. As said it just makes life difficult. I have a 102 Mak, rarely gets used.

 

On the Zoom side they tend to have narrower fields so the problem is not helped.

[Jon Isaacs]

Bob:

 

First: Hello and to CloudyNights.  On to your question:

 

A zoom for a 90mm or 102mm Maks:  I have the Baader Mk4, a Vixen LV zoom which is has a lanthanum element(s), and I have compared these to my friend Tom's Celestron zoom.  I tested them in a 10 inch F/5 Dob.  I suspect the Orion zoom is based on the Vixen LV zoom which was the standard zoom for many years.  

 

Anyway, in terms of image quality, the Vixen LV zoom ran a distant third to the other two. The Celestron was surprisingly good and only fell down at low powers where it wasn't as sharp "off-axis" as the Baader.  In an ~F/13 Mak, this wouldn't be an issue.  I measured the apparent field of view, the Baader was consistently about 5 degrees wider than the Celestron.

 

My own thinking is that for an Mak, the Celestron will be a very good performer and it would be smarter to invest more money in the scope and mount than to buy the Baader zoom.

 

Jon

[Elfbob]

The argument for getting the Celestron and putting the savings into a better scope/mount seems like a good one. The only thing I’m curious about is how much of a discernible difference is there between a 102mm vs 127mm? There’s about a 50% difference in aperture area, does this equate to a stark difference on a Mak? And 127mm runs almost $150 more than a 102 in most cases.

As to why I’m getting a Mak and why I want a zoom, simply put: Portability and Ease of Use. I want something smaller than I can pack up really easy in the car and take places, such as camping in the fall. And I’d like a good zoom because others will be using it and because I don’t think I want an EQ or other tracking/GoTo mount (probably going with an AltAz). And zooms are a simple concept for others I show the scope to when camping or such.

And why the planets, well because they’re awesome and dynamic and interesting. I may move on to DSO’s later on, but seeing the planets in real time sounds amazing!

Edited by Elfbob, 14 September 2019 - 07:52 AM.

[SeattleScott]

I think you have a good plan. For a high F ratio Mak there probably won’t be a world of difference between the Celestron and Baader. As for aperture, 50% is quite noticeable, albeit not dramatic. For the use case of planetary viewing with a Mak, I like the idea of the Celestron Zoom with 5” Mak better than Baader with 4”. However if you move on to DSO, the wider FOV of Baader will help. Or if you get a F5 or F6 Dob, the better correction of the Baader will help. So the Baader will grow with you better if your interest grows, but to me the Celestron is an almost obvious winner for the use case presented.

Scott

[jaraxx]

I have a 127 Mak and a Baader Zoom and they work well together. But with the high f ratio, I think the Celestron is very acceptable. And if the choice is the Baader and the 90 / 102 or the Celestron zoom and a 127, I'd take the 127 package, tho it might require a bit more of a mount.

I will say that the Baader is an eyepiece that you can keep for a long time and it does well in scopes with low focal lengths. I think it's a good long term investment.

[Jon Isaacs]

Regarding the Celestron zoom with the 127mm Mak and the Baader with the 102:  This is my all time favorite quote.  It's by Jean Texearu who wrote the amateur telescope maker's bible How to Make a Telescope.

 

"It is not usually made clear, that these elements, objective and eyepiece, are by no means comparable in importance. The astronomer's hopes are almost wholly tied to the size and quality of the objectve. The objective of even the smallest telescope, because of its larger dimensions, the severe optical requirements it must meet, and the difficulty of its construction, completely overshadows the eyepiece."

- "How to Make a Telescope," by Jean Texereau, Page 1, Paragraph 2.

 

In this case, the difference between a 102 Mak and a 127 Mak is significant, it's more resolution and more light.  The Celestron Zoom eyepiece is around $65.  If at a later date, a Baader is wanted, you're only out $65 and in reality, the Celestron could be sold for probably $45 so there's a minimal cost to switching.  With the scopes, the cost to upgrade will be much greater.  

 

Jon

[Elfbob]

First off, thank you guys so much! So many good thoughts and replies. I really do appreciate it!. I feel like I’m going to get the Celestron zoom, with the Baader not showing a significant improvement in such a high F scope, and money better spent on the scope itself.

Now the internal debate for me is if I want to fork over an extra $150 for the 127mm or save the money. Seems kinda silly not to go for the 127, realizing that even with the 127 + Celestron Zoom, I’m still saving almost $80 in comparison to 102mm + Baader. And like the above post says, it’s much easier to upgrade the eyepiece than upgrade the scope.

The only thing that really confuses me is how much better is the 127mm be than the 102. Because while there is definitely a decent increase in aperture, the focal length is also increased, meaning that the improvement in the speed (f ratio) is somewhat marginal (12.1 vs 12.7). I guess I’m still confused about the difference in roles that the aperture vs the speed has. Is the aperture simply resolution and the speed is the light sensitivity. I don’t know, I guess this is where I begin to show my naivete in the subject. And I’m kinda getting away from the point, that question my be better suited in the beginners forum.

But you guys are awesome! Thank you for all your insight. It goes a long way in helping me.