29 replies to this topic

[Jesse7Mak]

I got a solar filter for my Meade 7” Mak to prepare for the April 8 eclipse.  Come to find, a 40mm focal length eyepiece brings the field of view to the limit for is scope, not enough to see much of the corona, though it does just show the complete solar disc.

 

So, I tried to sketch the sunspots I could see by hand.  Here are a couple of consecutive days’ sketches:

 

Of course, seeing is unlikely to be consistent from day to day.  What I really wished I had was an eyepiece with a grid on it, so I could then draw a circle on graph paper and much more accurately sketch what I see.

 

I couldn’t find such an eyepiece available to buy.  I’m hoping my search-fu was defective.  Do such eyepieces exist?

[pcrichmond]

Wonderful sketches. I'm waiting for white light filters to be available once more so I can pair a dual system setup. Currently view in Ha.

Not sure of an eyepiece with a grid but some of the older reticle ep's had the dual parallel lines and the clock both etched in that might be good enough for your reference points. Don't remember these going much lower than 15mm though.

Hopefully someone else will be able to send you in the right direction for the ep.

Look forward to seeing more of your sketches.

[columbidae]

I've been searching for graduated reticle telescope eyepieces off and on and it just doesn't seem like there's any ready-built options available right now.  There are posts about DIY versions, but I haven't tried anything in that vein quite yet.

 

Otherwise, very nice sketches!

[Special Ed]

Nice work on those sketches.  Placing the sunspot groups accurately comes with practice.  You can also divide the solar disk into quadrants in your mind to help with placement and/or use a template divided into quadrants and tick marks around the limb.

[Jesse7Mak]

Nice work on those sketches.  Placing the sunspot groups accurately comes with practice.  You can also divide the solar disk into quadrants in your mind to help with placement and/or use a template divided into quadrants and tick marks around the limb.

That’s exactly what I did!  I put the big spots in first, then come back to each group to fill in more details as I see them.  A bit of patience showed a few more of the smallest spots.

I drew them at different times of day, so north is in different places. I’m not so pleased with my two sketches’ consistency. They don’t overlay each other well.

 

I might try a different clipboard, that lets light through.  If I’m clever, I could make a shallow light box that’s lit by the sun from beneath the paper.  That way, I could lay a blank piece of paper over yesterday’s to repeat the big spots that are the same from one day to the next.  Then, draw the smaller spots again. 

 

The thing is, with my Meade 7” Mak, the only eyepiece I own that will give me the entire solar disc is a 40mm.  I couldn’t find a 40mm with even basic cross hairs.

 

I hate to try to take one of these eyepieces apart to insert a grid near the focal point, nor do I know exactly where that is, or how to fabricate a fine grid…. 

Edited by Jesse7Mak, 18 April 2024 - 05:18 PM.

[pcrichmond]

Perhaps your 40 ep with thin fishing line taped to the barrel end to give you the quadrants?

Might be worth the experiment.

[bphaneuf]

I’m with Michael. You can mentally overlay a clock face over the FOV of your eyepiece. With a little time and practice you’ll become quite proficient and accurate. You can practice with photos if the clouds aren’t cooperating and/or in the evening if you’re not pursuing night sky objects.

-b

Edited by bphaneuf, 18 April 2024 - 09:20 PM.

[Special Ed]

...I might try a different clipboard, that lets light through.  If I’m clever, I could make a shallow light box that’s lit by the sun from beneath the paper.  That way, I could lay a blank piece of paper over yesterday’s to repeat the big spots that are the same from one day to the next.  Then, draw the smaller spots again... 

 

 

Well, the problem with that is the sunspot groups would have rotated with the Sun and wouldn't be in the same places.  Also, the Sun is dynamic and the sunspot groups (technically called active regions) change in size, shape, and appearance.  That's one reason why the Sun is so fascinating to observe.

[Jesse7Mak]

Today’s work.  
 

 

Pretty soon, I’ll get that iPhone bracket in the mail, and I can just grab a photo of these.  There’s something nice about viewing it for a few minutes and drawing it by hand, though.  Time spent pleasantly.

 

The circle is a Corelle cereal bowl.  I have a couple hundred sheets of A4 paper we brought with us from Europe, which fit nothing over here.  Good drawing paper.

Edited by Jesse7Mak, 22 April 2024 - 06:03 PM.

[PXR-5]

Very nice work Jesse!

[Jesse7Mak]

Very nice work Jesse!

Thanks.  Looks like that’s it for clear skies for a few days.

 

Jess

[Jesse7Mak]

Here’s what I saw today:

 

 

Rain clouds moving in this afternoon, but it looks good for Thursday and Friday!  Very windy today, I had to remove the sun shade from around the solar filter, it was acting as an excellent sail, bouncing the telescope around a bit.  Hand drawing these sunspots still works, as I can just wait for the gusts to subside.

 

I think my telescope reverses east-west, but maintains north-south orientation.  I’ll have to confirm that and figure out how to mark my drawings’ cardinal points.  Right now, I’m just drawing them as I see them, and that changes with how the star diagonal is oriented to the telescope, which depends on which half of the sky it’s pointing it, so I can keep my head away from the finder scope eyepiece.

 

I wish I had a finder scope with a right angle eyepiece instead of the straight finder scope that came with the telescope.  Likewise for the polar alignment scope.  Getting down beneath the mount to use that polar alignment scope isn’t so nice.

 

Today, I masked the bottom of my tripod legs and painted their positions onto my driveway.  Now, I’ll be able to duplicate polar alignment awfully closely without having to get out my compass to align the tripod, then level it, then polar align, every time I observe. A quick check in the polar alignment scope will get me going.  Trees all around me, so I’m never going to get a good view of any place on the horizon.  I picked a spot on my driveway with the best all around views.

 

[bphaneuf]

That's a great idea to mark the tripod legs on your driveway.  We did something similar to get the 24" close to Polaris for alignment.  You're right that it saves time and effort.

-b

[Jesse7Mak]

That's a great idea to mark the tripod legs on your driveway.  We did something similar to get the 24" close to Polaris for alignment.  You're right that it saves time and effort.

-b

Thanks.  It seemed the thing to do.  Anything that shortens the work flow turns into more time to observe!

[Special Ed]

Your 22 and 23 April sketches look good! Those busy sunspot groups are not easy to record--well done.

To figure out the cardinal directions for your Mak-Cas, turn off the drive and watch the direction of the Sun's drift. That is roughly celestial west. 90 degrees clockwise from there is celestial north.

[Jesse7Mak]

Your 22 and 23 April sketches look good! Those busy sunspot groups are not easy to record--well done.

To figure out the cardinal directions for your Mak-Cas, turn off the drive and watch the direction of the Sun's drift. That is roughly celestial west. 90 degrees clockwise from there is celestial north.

Thanks.  Will switch off the drive next time to see.

 

I do the sketch in phases.  Imagining a clock face, I first sketch the biggest spots, estimating their distance from the center to the edge.    Then, I start adding medium sized spots, judging their distances and directions to other big spots. Once I get the main groups put down, I can take my time to fill in the details of the smallest spots, and the “shadows” around some of the bigger spots.

 

I tried switching out to a 26mm eyepiece to focus on each sunspot group for more details.  But, it didn’t really help today.  Perhaps on a day with better local seeing.

 

The iPhone bracket arrived today.  The predicted rain clouds have not yet arrived, so this gave me the first chance to test setup using the tripod marks I painted on the drive this morning.  Wow, that sure made setting up a lot quicker and easier.

 

But, my 40mm eyepiece has quite long eye relief, taking the z-axis adjustment of the phone bracket to its limit.  This let incidental light bounce around between the eyepiece and the phone.  Also, it’s so bright in broad daylight, it’s nearly impossible to see the phone display.  Finally, the phone couldn’t figure out its auto-focus.  Of a dozen shots, this one is the best, and it’s not very good.  I can do far better by hand.

 

 

I’ll certainly need an app to better control the iPhone camera.  A dark shroud over the back of the scope will also go far to eliminate incidental light at the camera.

 

It’s never just easy.

Edited by Jesse7Mak, 23 April 2024 - 01:34 PM.

[Jesse7Mak]

I tried a different disc template today, a plastic coffee can lid in the center of which (marked by the plastic casting sprue) I poked a hole to mark the center of the circle on the paper.  That way, I only have to guess where the center of the view in the eyepiece is.  And, I switched off the drive to see which part of the disc touched the edge of the field of view first to mark west.  Since the view on my telescope using a star diagonal doesn’t invert north-south, I drew in north on this drawing ninety degrees counter clockwise.  Edit to add:  Which was a mistake.  North, in my view, is ninety degrees clockwise from west.  Replaced the phot of my sketch with a corrected version.

 

Edited by Jesse7Mak, 25 April 2024 - 04:24 PM.

[niteskystargazer]

Jesse,

 

Very nice Sketching sunspots  .

 

CDS,KLU,

 

 ,

 

Tom

[Jesse7Mak]

Jesse,

 

Very nice Sketching sunspots  .

 

CDS,KLU,

 

 

Tom

Thanks, Tom.

[Jesse7Mak]

Here’s today’s sketch.

 

I sent an email to the Solar Dynamics Observatory, and confirmed their images show north up.  Edited to add:  I replaced my image with a corrected version.  I had it wrong.  In my eyepiece, north is ninety degrees clockwise from west.

 

And, wow!  It was cold outside this morning at 03:00 local.  23 degrees F.  Winter boots, parka, mittens, wool watch cap.  I stayed nice and toasty.

Edited by Jesse7Mak, 26 April 2024 - 07:07 AM.

[Jesse7Mak]

Your 22 and 23 April sketches look good! Those busy sunspot groups are not easy to record--well done.

To figure out the cardinal directions for your Mak-Cas, turn off the drive and watch the direction of the Sun's drift. That is roughly celestial west. 90 degrees clockwise from there is celestial north.

I reversed this on my sketches.  Thanks for the tip.

 

J

[Jesse7Mak]

Today’s sketch:

 

 

What a pleasant afternoon.  Perfectly clear skies.  These are the good old days.

[Jesse7Mak]

This is about as good as it’ll get here for a few days:

 

 

I’ll be back when the sun returns!

[Jesse7Mak]

Ha!  I beat the weatherman today!  A big patch of blue sky came overhead!

 

It only takes three or four minutes to set up, now that I have those spots marked for the tripod legs.  That really makes the difference.  And, as I post this, I see a new band of clouds coming from the west.  Quick setup helps me catch a sketch.

 

Today’s spots:  not as many active regions visible as there has been.

 

[rishi]

Nice sketches. Sharing my attempt from today: 

 

 

 

 

Attached Thumbnails

•