Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

COUNTING SUNSPOTS WITH A $10 OPTICAL TUBE ASSEMBLY

  • Please log in to reply
25 replies to this topic

#1 retroformat

retroformat

    Vostok 1

  • -----
  • topic starter
  • Posts: 118
  • Joined: 15 Nov 2020

Posted 03 July 2022 - 04:16 PM

I encourage anyone with a minimum of technical facility to build their own vintage solar telescope, and join with me on the sunspot counting journey. Next to the study of Earth-grazing asteroids, I can think of no more important branch of astronomy. Aside its obvious ties to climate change science, solar astronomy is extremely important to our understanding of, and ability to predict flares and coronal mass ejections, which have the potential to devastate modern society (google "Carrington Event").

Click here to view the article
  • scottinash and notanobis like this

#2 texcoco

texcoco

    Mariner 2

  • *****
  • Posts: 240
  • Joined: 19 May 2018

Posted 10 July 2022 - 11:08 PM

Sir, this is a familiar topic. I have just recently been looking at lenses for building a very similar scope. Can you provide a source or part number for the lens?


  • CharlieM likes this

#3 lwbehney

lwbehney

    Apollo

  • *****
  • Posts: 1,253
  • Joined: 06 Mar 2018

Posted 13 July 2022 - 11:23 AM

This is very cool. I have an old refractor, which has a lens cover with a two inch diameter stop down aperture. I have a mylar sun filter I can put over the lens cover and I could take a photo of the solar surface with my iPhone. If I used an eyepiece with a  magnification of 25X, would that be too much for this purpose?

Thanks for posting this idea.

-Larry



#4 careysub

careysub

    Gemini

  • *****
  • Posts: 3,112
  • Joined: 18 Feb 2011
  • Loc: Rancho Cucamonga, CA

Posted 18 July 2022 - 11:34 AM

This lens from Surplus Shed, for $1.50, will do it:

 

https://www.surpluss...tem/L1918D.html

 

50mm x 1000mm

 

I have several of these for making Galileo facsimile scopes.

 

I use 2" cardboard tubes also, they are just right. Galileo used cardboard tubes himself, I'll bet sunspot spotters (sunspotters?) did the same.

 

Maybe not needed for this project, but the inside of the tube is easily blackened by pouring diluted flat black paint through it.


  • wrvond and Brianm14 like this

#5 Astrojensen

Astrojensen

    James Webb Space Telescope

  • *****
  • Posts: 16,565
  • Joined: 05 Oct 2008
  • Loc: Bornholm, Denmark

Posted 21 July 2022 - 04:06 PM

I also wanted to participate in this project, so I bought some lenses on ebay, identical to the one shown in the article (the box is completely identical), but the optical quality turned out to be so poor, they can barely form a recognizable image. I bought four, and one of them turned out to only have 70cm focal length. The three others are so horribly poor, Jupiter is a giant smear, 1/10 the size of the Moon(!). On either side of focus, Jupiter is drawn out in a long string, almost the width of the Moon... And this is at 25mm aperture. Optically true my butt. Galileo's scope was vastly superior. 

 

 

Clear skies!

Thomas, Denmark 


  • elrod and Brianm14 like this

#6 Brianm14

Brianm14

    Viking 1

  • *****
  • Posts: 609
  • Joined: 21 Jun 2021
  • Loc: NC

Posted 01 September 2022 - 04:34 PM

After obtaining the 50 mm x 1000 mm objective lens from SurplusShed, I have a few questions about assembling this telescope.  Can anyone help?

 

-For the tube, can 2” PVC pipe be used (perhaps) instead of cardboard?  It’s just something I might want to consider.

 

-Where is the best place to start looking for 2” diameter cardboard tube?

 

-What is the best way to mount the objective lens?  What sort of glue should be used?

 

-For the ocular, I am thinking of mounting one of several Huygens eyepieces I have collected.  Is a simple slip tube the best way to approach focussing?

 

Any suggestions are most welcome!

 

CS,

Brian



#7 Brianm14

Brianm14

    Viking 1

  • *****
  • Posts: 609
  • Joined: 21 Jun 2021
  • Loc: NC

Posted 01 September 2022 - 04:37 PM

This lens from Surplus Shed, for $1.50, will do it:

 

https://www.surpluss...tem/L1918D.html

 

50mm x 1000mm

 

I have several of these for making Galileo facsimile scopes.

 

I use 2" cardboard tubes also, they are just right. Galileo used cardboard tubes himself, I'll bet sunspot spotters (sunspotters?) did the same.

 

Maybe not needed for this project, but the inside of the tube is easily blackened by pouring diluted flat black paint through it.

Careysub, Love the photo of the great poet/short story writer/essayist, Jorge Luis Borges.  Been reading him since1971.  Still thrills me!


  • careysub likes this

#8 careysub

careysub

    Gemini

  • *****
  • Posts: 3,112
  • Joined: 18 Feb 2011
  • Loc: Rancho Cucamonga, CA

Posted 02 September 2022 - 12:04 PM


 


 

-Where is the best place to start looking for 2” diameter cardboard tube?

 

-What is the best way to mount the objective lens?  What sort of glue should be used?

 

-For the ocular, I am thinking of mounting one of several Huygens eyepieces I have collected.  Is a simple slip tube the best way to approach focussing?

I got 2" cardboard tubes from FedEx stores, I also found them at OfficeMax. It is a standard size mailing tube, very common. You can also order them on Amazon, or other on-line shipping supply stores though they usually cost more since you can't buy just one and there are shipping charges.

 

I mounted the lens using low profile adhesive weather stripping to make the support just inside the front of the tube, then using silicone or E6000 styrene-solvent based adhesive - but literally any household adhesive will work. I would use one though that allows you to remove the lens later in case you want to reposition or something.

 

Slip focusing works fine. You can make a slip focuser by cutting a small segment out of a piece of 2" tube and taping it back together.

 

I think cardboard is easier to work with that PVC (not that that is hard) since it takes adhesive and paint well and is easily cut. You can apply a waterproofing sealant to it if you like (paint can do that too depending on type).
 


  • Brianm14 likes this

#9 careysub

careysub

    Gemini

  • *****
  • Posts: 3,112
  • Joined: 18 Feb 2011
  • Loc: Rancho Cucamonga, CA

Posted 03 September 2022 - 02:15 PM

Careysub, Love the photo of the great poet/short story writer/essayist, Jorge Luis Borges.  Been reading him since1971.  Still thrills me!

I like to use him as an avatar because although he was blind most of his life he had cosmic vision.


  • Brianm14 likes this

#10 Brianm14

Brianm14

    Viking 1

  • *****
  • Posts: 609
  • Joined: 21 Jun 2021
  • Loc: NC

Posted 04 September 2022 - 09:11 AM

Thanks, Careysub!  Great suggestions!

 

Really like your reasons for using Borges’s photo.

 

Brian


  • careysub likes this

#11 retroformat

retroformat

    Vostok 1

  • -----
  • topic starter
  • Posts: 118
  • Joined: 15 Nov 2020

Posted 10 September 2022 - 04:12 PM

Sir, this is a familiar topic. I have just recently been looking at lenses for building a very similar scope. Can you provide a source or part number for the lens?

Sorry for the delay in my reply!  The lens I got from an eBay seller "Spiratronics" - <https://www.ebay.com/itm/121183854320>   For this sunspot counting project, any simple lens, bi-convex or planar-convex, with a focal length of approximately 100cm, will do.  So if the above item is not available, do not despair.



#12 retroformat

retroformat

    Vostok 1

  • -----
  • topic starter
  • Posts: 118
  • Joined: 15 Nov 2020

Posted 10 September 2022 - 04:14 PM

This lens from Surplus Shed, for $1.50, will do it:

 

https://www.surpluss...tem/L1918D.html

 

50mm x 1000mm

 

I have several of these for making Galileo facsimile scopes.

 

I use 2" cardboard tubes also, they are just right. Galileo used cardboard tubes himself, I'll bet sunspot spotters (sunspotters?) did the same.

 

Maybe not needed for this project, but the inside of the tube is easily blackened by pouring diluted flat black paint through it.

Thanks for that tip!  I probably should have blackened the interior of my tube, but did not think of it.  Now I am several months into my time-series of data with this scope, and will not change (i.e. improve) it.  But what I might do is make a second one, blacken the interior, and see if the results are any better.  



#13 retroformat

retroformat

    Vostok 1

  • -----
  • topic starter
  • Posts: 118
  • Joined: 15 Nov 2020

Posted 11 September 2022 - 04:14 PM

I also wanted to participate in this project, so I bought some lenses on ebay, identical to the one shown in the article (the box is completely identical), but the optical quality turned out to be so poor, they can barely form a recognizable image. I bought four, and one of them turned out to only have 70cm focal length. The three others are so horribly poor, Jupiter is a giant smear, 1/10 the size of the Moon(!). On either side of focus, Jupiter is drawn out in a long string, almost the width of the Moon... And this is at 25mm aperture. Optically true my butt. Galileo's scope was vastly superior. 

 

 

Clear skies!

Thomas, Denmark 

Thomas:  I only ever purchased one of those "optically true" lenses, so I know nothing about the consistency or predictability in their quality.  It does seem to perform as expected... Maybe I just got lucky?  I'm curious about this, because maybe mine is just mediocre, and I could get a better one??  I've already placed an order for two of the $1.50 Surplusshed.com lenses that Careysub recommended.  I plan to build a second "galilean" scope and compare results, just out of curiosity.  Anyway, Leif Svalgaard's sunspot counting project prefers a diversity of observers, along with a diversity of optical systems in use (approximately 1 meter focal length, 1 inch aperture), because actually very little is known about the optics that the ancients used.  

Is your knowledge of Galileo's telescope performance based on what you've seen of his drawings, or do you have other sources?



#14 Brianm14

Brianm14

    Viking 1

  • *****
  • Posts: 609
  • Joined: 21 Jun 2021
  • Loc: NC

Posted 19 September 2022 - 09:54 PM

Sprayed two coats of Rustoleum camouflage flat black into my cardboard tube on top of a single coat of gray primer (primer is an easy precaution).  Good stuff.  Very flat, very black.



#15 KI5CAW

KI5CAW

    Ranger 4

  • -----
  • Posts: 336
  • Joined: 07 Nov 2019
  • Loc: East Mountains, New Mexico

Posted 09 October 2022 - 06:48 PM

Did you use a 1700s eyepiece design?



#16 zombieregime

zombieregime

    Lift Off

  • -----
  • Posts: 1
  • Joined: 17 Nov 2022

Posted 17 November 2022 - 09:19 PM

Neat project and all but... If one "google(s) "Carrington Event"" they will find nothing but page after page of those who buy into the scaremongering and next to nothing on all of the failsafes and failovers in place that would mitigate much of the alleged 'sending us back to the stone age' destruction served up on the silver platter of click bait. Long wave EM, which is what we would experience, is only really an issue over long runs of wire. You know, like telegraph lines, or high tension power wires. High tension power lines that have pyrobolts to blast the line free if things get too spicy, and automatically actuated (some pneumatically) bus bar breakers, and block after block of disconnects and safeties that keep common every day things like lightning from frying your TV, where the only real issue is wild fires. And to some extent the massive transformers in city vaults. Yes, we would end up with outages, particularly when the grid completely disconnects literally everything at the slightest wobble during the event. However, no, not everything will fry. That view is entirely based on scare tactics using a few fires from the telegraph age (remember? long interconnected wires with little to no safety in place? remember that time? yeah, keep it in mind...) when we didnt have small electronics. SMALL electronics. As in far below the wavelength of EM that would happen. How good is your wifi router at picking up LW radio? Its not. Its crap at it. Wanna know why? Of course you dont, because "ERMUHGURD DA SUHN GERNNNA KEEL US!!!" sells better than being physical sciences literate. I cant count the number of times Ive driven by a 50kW radio tower and had my phone blow up in my pocket....oh wait, it hasnt. Or the videos people that film near million watt radio towers and their camera glitches out.....oh wait, it doesnt. Or when someone keys up their however-many-watt HAM rig and fries their laptop.....OH WAIT, THEY DONT!!! Our electronics are not on a size scale that will meaningfully interact with a strong, long, EM wave. Sure, some might glitch out and reset. but they will reboot just fine. Magnetic storage you think? Yeah, the thing about that is you need a rapidly oscillating (ie, short wavelength) EM field to affect that. if you bring the background magnetic field uuuuuuuup then dooooooooown most if not all of it will stay in tact. At least in tact enough for error correction to rebuild lost bits. Same thing with the traces in our small (remember? small? ESD protected? not from the telegraph age? remember?)  electronics, unlike a tuned antenna perfectly matching the wavelength of an EM source, the difference between the traces will not be greater than the brakedown voltage of any piece within them. Again, at worst the power monitoring circuits will trip and just simply turn them off. 

 

Will there be some destruction of utility industrial level equipment? Most likely. Will there be fires? absolutely. Will some electronics release the smoke? Sure, Ill put a dollar on that bet.

 

Will we be thrust into mad max times for the rest of our days because apparently our modern society can fathom living a few days or weeks without power? .....Well...... Lets just say I wont be traveling to Detroit during that time.... otherwise NO!!!! For the most part, backup generators will not be affected. Stores (with access to back up power, and I dont know if you noticed, portable generators strong enough to keep super market freezers online exist. Like they have been a thing for a long time) will still be able to keep their fridges cold. There is plenty of back stock of canned foods (no little jimmy, I dont care if you like lima beans, eat them or go to bed), dry foods, food making products (if you dont have some bread making yeasts in the cupboard....what are you doing with your life? Other than spreading scaremongering BS from ancient aliens levels of arrogant shysters....and feeling superior for it....), there are trees with fruit on them, plants with berries in them, animals to hunt..... So long as that gym rat alphabro douchenozzle neighbor you've whipped up into a frenzy over civilization ending cosmic events doesnt kick your door in, shoot you with his favorite AR-15 (short barrel, fore-grip, green laser, holo sight, you know the one, the one covered in every tacticool QuarterMaster addon he can get his hands on and calls Michelle), and take all your supplies....then for the most part we, as a species, will be fine. As long as people take the time to stop, think for a second, possibly ....GASP.... ask someone with experience with the types of systems they are afraid of being affected, and evolve the personal integrity to not prey on the ignorance and gullibility of their fellow man perhaps even act with some level of civil respect and responsibility that is.....Otherwise, yeah its the hordes of the ignorant that will usher us into the stone age, not the effects of a large CME.....

 

By the way, all you people already typing out replies, I have $20 that says EVERYTHING you have to say about those types of events comes from conflated opinions based on reports of the Carrinton Event fed to you over the course of decades from TV shows looking for shock value ratings. EVERY. SINGLE. WORD. I dare you to have an original thought. I DARE you..... So, go on, regurgitate that same tired garbage about electronics frying (addressed above) or transformers exploding (addressed above) or massive fires (addressed above, and agreed with no less). Put on a display your facade of intelligence which is nothing but peeling layers of echo chamber enforced lead paint. Show us how you follow like a good little lamb.

 

PS - yes I am aware of starfish prime. It knocked Hawaii off the grid. Notice how they didnt get thrust into the stone age? Notice how it just blew some equipment (connected to long electrical lines, by the way.... remember those?) with laughable, even flat out illegal, levels of electrical protection by todays standards? Yeah. If you only get your information from the history channel or discovery or (sadly) the science channel, you have no idea what you are talking about. A magnet past a coil, and conflating a city exploding erasing all industry and stored data across the planet because 'oh look! long power lines! EVERYBODY PANIC!!!' does not knowledge make. I would end with a satirical "change me mind" but why should I offer to be open minded to the people who already closed theirs off after it fell out?


  • Cosmo Geezer likes this

#17 retroformat

retroformat

    Vostok 1

  • -----
  • topic starter
  • Posts: 118
  • Joined: 15 Nov 2020

Posted 17 November 2022 - 11:04 PM

Did you use a 1700s eyepiece design?

No.  Simple two element Kellner, 25mm f.l.

To participate, there is no requirement to have an exact replica vintage telescope.  Just the approximation of one.


  • wrvond, LU1AR and Brianm14 like this

#18 mistercrisp

mistercrisp

    Sputnik

  • -----
  • Posts: 32
  • Joined: 17 Jul 2009
  • Loc: Sea Cliff, NY

Posted 12 December 2022 - 11:23 PM

This is very cool. I have an old refractor, which has a lens cover with a two inch diameter stop down aperture. I have a mylar sun filter I can put over the lens cover and I could take a photo of the solar surface with my iPhone. If I used an eyepiece with a  magnification of 25X, would that be too much for this purpose?

Thanks for posting this idea.

-Larry



#19 mistercrisp

mistercrisp

    Sputnik

  • -----
  • Posts: 32
  • Joined: 17 Jul 2009
  • Loc: Sea Cliff, NY

Posted 12 December 2022 - 11:34 PM

Hi Larry:  I am sorry that I am late to comment on your post.  I am thinking that your old refractor would most likely be a doublet - two lenses.  For this project, in an attempt to get telescope performance close to that of Staudach's telescope, we should have only a singlet lens which is what all of us in the project are using.  It has been suggested that the aperture for this project should be about one half inch to three quarters of an inch in diameter.  You wouldn't need any mylar film - instead you should project the image of the sun on something like a piece of metal or cardboard or masonite where you clip a piece of ordinary paper, and then you draw the sunspots that you see, with a pencil.  The idea is to duplicate, as much as possible the original conditions and methods.  So that wouldn't include photographs at all.  Just drawings.


  • retroformat likes this

#20 cobra967

cobra967

    Lift Off

  • -----
  • Posts: 1
  • Joined: 21 Feb 2023

Posted 21 February 2023 - 10:36 PM

Cool project! So, was the tube total length 1 meter?



#21 Brianm14

Brianm14

    Viking 1

  • *****
  • Posts: 609
  • Joined: 21 Jun 2021
  • Loc: NC

Posted 22 February 2023 - 01:02 AM

Yes.



#22 Gonariu

Gonariu

    Lift Off

  • -----
  • Posts: 10
  • Joined: 26 Sep 2023

Posted 08 October 2023 - 09:26 AM

Hi, I read about this project recently, I would like to participate, do I still have time or has it ended?



#23 retroformat

retroformat

    Vostok 1

  • -----
  • topic starter
  • Posts: 118
  • Joined: 15 Nov 2020

Posted 08 October 2023 - 09:49 PM

Hi Gonariu:

The project is still going on, with about a half dozen observers world-wide participating.  Leif Svalgaard at Stanford University coordinates the observations, and you should contact him with your question(s).

We also have a groups.io discussion area, FYI.

https://groups.io/g/sunspot-counters

Looking forward to seeing you join the group!

Boris



#24 Gonariu

Gonariu

    Lift Off

  • -----
  • Posts: 10
  • Joined: 26 Sep 2023

Posted 09 October 2023 - 01:02 PM

Thanks Boris, these days I've been building a vintage 17th century style telescope, I have practically everything at home (55 mm lens, two cardboard tubes, scotch tape). I would like to ask you what glue you used to attach the single lens to the cardboard tube. Thank you, clear skies!



#25 retroformat

retroformat

    Vostok 1

  • -----
  • topic starter
  • Posts: 118
  • Joined: 15 Nov 2020

Posted 09 October 2023 - 01:11 PM

I used a common PVA glue (like Elmer's glue or wood glue).  Sorry my original article did not specify this.


Edited by retroformat, 09 October 2023 - 01:12 PM.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics