Building an 150mm Newtonian scope - From concept to results - Forums

Topic starter

Jul 31, 2022 · Edited: Jul 31, 2022

Hello community,

A while back I decided to build my own telescope. Mainly driven by 2 reasons:

1.       Cost-Benefit: I was looking for a 6” Newtonian telescope, and I couldn’t find one with the specs I wanted. I thought I could build a scope higher in specs and more affordable than the options available.
2.       Learning: I wanted to know everything about my scope, therefore I would be able to debug and improve it in each aspect over time. Not saying I am a DIY type of person, so I enjoy the fact to use smtg I have built.

With it finalized I can say I am pretty satisfied with item (2), I have learned a lot and I am slowly improving the scope more in each detail, knowing what are the weak points it has. Item (1) I think I was too optimistic J, in the end it was not compensating so much in fact of the huge work. But one of the biggest reasons were related to availability of products and import taxes. Plus doing in parallel of being a new dad took me 1.5 years :-)

Without more delays I will divide this Thread in the following Posts:

1)      Summary and Result
2)      Parts Detail and Project
3)      Proof of Concept
4)      Building the CF Tube
5)      Building the holders for the Tube
6)      Building the Tube Caps
7)      Performance
8)      Future Upgrades

Helpful Insightful Respectful Engaging

Fabiano R. Maioli

Topic starter

Jul 31, 2022

Summary and Result

I will start from the end. So, you can decide if it worth to look further or not.

I have an Orion Sirius EQ-G mount with Rowan Belt modification, this mount is the same as the famous Skywatcher HEQ5. It gives a great tracking, typically between 0.5 and 1 arcsec, and I didn’t have plans to change it. One of the goals was to maximize the use of this mount without overloading it too much. Therefore, I chose to make a scope with 150mm aperture. 200mm could be an option and maybe it would benefit more of the large secondary needed, but I decided to go for the smaller also considering price and transportability.

Overall Specs:
-         Aperture: 150mm (aprox 6”)
-          Focal Length / Ratio: 600mm (F4)
-          Focuser: 2”
-          Tube Material and parts: Carbon Fiber

Here you can see the result, which I will detail in next posts how I built, including the performance.

Final Scope:

Helpful Engaging

Claudio Tenreiro

Jul 31, 2022

Looking forward to the next sessions. You are right, I recently received a Newtonian after waiting for its delivery nearly a year… Regarding the cost/benefit, maybe the valuable experience you got now could leverage/compensate the cost of the time invested in the project.
CS!

Dark Matters Astrophotography

Jul 31, 2022

Nice work! Eager to hear more about the project.

Fabiano R. Maioli

Topic starter

Aug 3, 2022

2) Parts detail and Project

a) Primary Mirror, Primary Holder and Focuser

This is an 150mm Orion UK Ultra Grade Mirror. It has Strehl 0.987, 1/10 PV, 1/55 RMS. Below the Zygo Report.

In fact, I bought an entire VX6 Scope from OrionUK to reuse the Primary Holder and Focuser also.

The mirror and focuser seems to be good quality. The positive aspects stop here, I had multiple problems with the post sell (double taxation) and primary holder with them. I don’t want to go in details, but if you would like to know why I will never buy again from them you can find details in this post: https://www.cloudynights.com/topic/790891-orion-uk-oouk-my-experience/

b) Secondary Mirror, Holder and Spider

I bought them from Astrosystems USA. I super recommend, great service. Only small complain I have is that the screws are all in Imperial units, so hard to find here in Europe in case needed.

The secondary mirror is in fact Antares brand, it is 2.6” (aprox 66mm) and an astonishing 1/38 PV and 1/167 RMS. Below the Zygo Report.

c) Tube, Holder, Caps: All are in Cabor Fiber and done by me. I will detail them in next Posts.

d) Tube Project Data

I used Newt for the Web to calculate the data. Considerations I did:
- I will use a 2” focuser and I don’t plan to use sensors bigger than APS-C in the future.
- I discounted some millimeters from the Secondary, as the holder from Astrosystems has a border.
- I projected considering the use of a Paracorr Type-2 Comma Corrector, which has a zoom effect of 1.15x, but shifts the focal point 47mm out. This is great, as requires a smaller secondary to cover the same amount of illuminated area compared to a comma corrector that does not move the FP.
I know, this makes the scope a bit slower, but the size of a secondary is more critical for a small primary mirror than it would be for a bigger one.
I also calculated in a way the Paracorr would not stay inside the tube while in focus. Below the details used:

I decided to not use Baffles, keep the diameter of the tube a bit smaller (again secondary constrains) and flock the final tube.This is it for this post. I will continue later!

Helpful

Dave Erickson

Aug 3, 2022

Very nice project, congratulations!!
Best regards,
Dave

Well Written Respectful Supportive

Veteran03

Aug 3, 2022

Hi there. Complete newbie here and was wondering what my investment would be in a setup to gaze and maybe capture some incredible shots that I see in these photo shots? I’m a complete beginner, sorry if this is the wrong place to ask!

mike

Andy Wray

Aug 3, 2022 · Edited: Aug 3, 2022

Hi there. Complete newbie here and was wondering what my investment would be in a setup to gaze and maybe capture some incredible shots that I see in these photo shots? I’m a complete beginner, sorry if this is the wrong place to ask!

mike

Mike,

It is in the wrong place as you should probably start a new topic under the equipment forum. I'll try and answer the question anyway by saying my wife spent about £2000 on my first scope and mount to get me into the hobby and our joint total spend over a few years has been about £4000 to do some reasonable astrophotography.

There are many people on here who have spent £10k to £30k+ on equipment and some spending more than my house is worth. You can have a lot of fun with a few thousand pounds budget (it's not hundreds of pounds though).

[sorry if you are not in the UK, but around the world the cost is about the same in US dollars ... i.e. I could have bought my kit for $4000 in the US]

Helpful

Veteran03

Aug 3, 2022

Thank you for the help! Exactly the info I was looking for so it’ll help a lot as I begin my studies. I’ll do better to find the right forums from here on out, I’ve just been browsing around now all the different ones available and the work and studies people have shown are incredible. Again thank you for the help!

mike

Respectful Supportive

Fabiano R. Maioli

Topic starter

Aug 3, 2022

Yep, I agree with Mike. It doesn't mean you can't make miracles with cheaper/simpler rigs. And in fact it is recommended to start smaller to see if you really enjoy nights without sleep before putting more money on it. But, usually it will bring some frustrations, and more money is needed to improve and be able to sleep more too.
In fact, the whole progress journey is part of this hobby. Having a super rig at first wouldn't be the same. At least IMO.
Best.

Claudio Tenreiro

Aug 3, 2022 · Edited: Aug 3, 2022

and maybe capture some incredible shots

Hi, I believe you may find similar topics if you surf through the Forum, however the sentence that I quote from your post, and as you can imagine from the previous two answers, it is dificult that someone can give you an especific answer to it. Tha later because it depends on what you call "incredible", that may starts from an equipment based on a CDK14 Planewave scope and up. Or, you can get amazing images using a top ED80 refractor, or similar ones.

If you allow me to give an advice, put the question the other way around, what you may whant to achive and look at what equipment was used in those cases by other people. I am Just talking about the stuff (or gear), but, very importantly, or even more important is that, the final result you see, normally depends on the skills you need to build up to extract the best of your data, sometimes the so called steep learning curve, the one you need to master the different software analysis that goes with it.

It is a not so short journey and you need to be patient, manage frustration and just go, it is amazing what you can achieve with not so sophisticated equipment.
CS ! and all the best.

Related discussions

17 things I did during the last year to greatly improve my astrophotography

17 things that I did in the last year that improved my astrophotography. Hi, I am an amateur astrophotographer. I have spent about 10 years doddling with it, even taking a 3-year break during the pandemic due to work commitments. I came back to it in...

Astrophotography improvements relevant to telescope building and optimization goals.

May 22, 2024

Large telescopes and seeing - what does make sense?

Hi out there, an often asked question brings up a thought I have for a long time and I'm not sure if I answered it to myself correctly. So I'd like to ask for some explanations to help me understand this better. There is always this recommend...

Telescope sizing and performance directly applicable to 6" Newtonian specifications.

Feb 4, 2024

Hotech Advanced CT Laser Collimator - What is causing this?

Greetings, I purchased the Hotech CT Collimator and have had a difficult time getting good results with it. I have watched the instruction videos multiple times over and I think I understand the concept well, but my collimation still suffers. My use ...

Collimator tool maintenance essential for telescope alignment and debugging.

May 2, 2024

Remote hosting considerations

Hi All It becomes gradually more and more frustrating that I have all this great equipment - but NO clear skies So I am slowly starting to consider remote hosting options and are curious to get some feedback on a few thoughts. Telescope focal length?...

Remote hosting solves clear skies problem for telescope observation use.

Mar 2, 2024

Hello from San Diego!

Hi friends! My name is Daniel and I am just starting in astrophotography. I work as a research scientist during the day and have a background in cryo electron microscopy, which uses CCD/Direct Detection cameras and similar corrective software as astr...

DIY telescope building relevant to beginner astrophotography equipment setup needs.

Jan 2, 2021