Backyard observing in the city

[Thor]

Recently retired, and recently confined, I am interested in spending more time observing at home. Living within Minneapolis I always thought I must travel to remote places for this activity.

But in this last year I recall attending an MAS meeting and learning about a backyard observatory built by an MAS member in a similar residential neighborhood. I wish I could recall his name, because I would like to know more about the nature of observing in extremely light-polluted skies. I got the impression he had plenty of interesting projects he was engaged in and that while the city lights precluded much, there was still plenty of stuff to explore.

Does anyone on this list recall that presentation? And of those members who do urban observing, what are your experiences/recommendations?

Thor.

[FF2Rydia]

Was it Russ Durkee, and his Shed of Science Observatory?

[markjob]

YEP. Russ Durkee, he moved his rig to Texas.
He and I are sharing an observatory NW of Austin about 90 minutes.

[Deane Clark]

Hopefully Russ will notice this and chime in. I believe he was doing asteroid photometry, but the light pollution finally became insurmountable.

As for recommendations, stick to bright things! Jupiter, Saturn, and Mars should be great targets this year. Let’s hope for no Martian dust storms this time.

Congratulations on retirement!

[merle]

Was it Russ Durkee, and his Shed of Science Observatory?

I ran across this Gemini issue about Russ from 2005.

http://oldsite.mnastro.org/gemini/files ... 200506.pdf


Merle

[Thor]

Thanks Merle and others for the references to Russ Durkee's work. I think I will try some simpler projects to start out with, like say, observing the moon. There is also an Urban Observing Program by the Astronomical League. Sounds like a good place to start. I'll let you know how it goes.

[clayton]

Thor

I think Kevin Johnson might be a good contact for the trricks on observing in the city. I think he did much of his Master observer award from Bloomington with a ten inch. Suresh does a good bit from his home in Hopkins. He probably has some wisdom to share too.

I have been out a few times this year in my Southwest Woodbury yard to look for deep sky objects and comet hunting. It seems its gotten brighter over the years. My sky is really impacted by humidity and low clouds; even more so than a dark site. Any little atmospheric issue to scatter or reflect light pollution downwards is magnified due to the amount of LP.

I get a SQM of 19.10 -> 19.4 when decent, Bortle 6 by some maps, Maybe trending to a Bortle 5+ and on really good nights. Only targets higher than 25-30 degrees are reasonable most of the time.

However it's sometimes so bad it's such a grey and washed out mess and I end up frustrated after only an hour and find myself moving all my eq back inside.

I have never used LP filters that much but I think I am going to try to remember to use them more often. My Dobs upper tube is not big enough for a filter slide and screw in filters mean I have to swap it around eyepieces.

Maybe a Zoom might be worth it as I think the light pollution kind of negates the need for the high end eyepieces.

I have used a dark observing cloth in the past too block neighborhood lights.

My small refractor on lunar and the planets is fairly good. The brighter double stars too. I can't really complain there.

[FF2Rydia]

There is also an Urban Observing Program by the Astronomical League. Sounds like a good place to start. I'll let you know how it goes.

That and the two Lunar Observing programs are the logical starting points. Maybe Double Stars as well.

[BradNasset]

Lots of Messier objects are fuzzy galaxies that are pretty much invisible in a bright sky. However, a number of Messier objects are 'open clusters' of stars- groups of stars that just about fill the field of view in a lower/mid power eyepiece. Your field of view in your eyepiece looks like a mini universe, with little groupings of stars that just as well could have constellation names all for themselves. They are fun to observe, and are pretty visible in lighted skies. Have fun.

[Sureshks]

Hi Thor,

With light pollution ever-increasing, this subject is becoming more and more important. Obviously, if you're observing from the city, you are generally limited to the planets & Moon, globulars and open clusters, and perhaps the brightest galaxies, such as Andromeda.

Back 30 years ago, I did the entire Messier list of most of the Herschel I list with a C8 from my parents' home, about 20 miles from downtown Chicago (which is much brighter than Minneapolis). So I know that it can be done. Colder air, which holds less moisture and particulate matter, also seems to mitigate light pollution a bit. So there's (unfortunately) an advantage to doing urban observing on the coldest winter nights vs. the summer. It's exasperating seeing a city's light dome expand during the summer.

When doing urban observing, I usually wait till after 10 or 11pm, when most people turn in for the night and (hopefully) turn off their lights. This probably cuts down the overall light pollution by 10-20%. When I was completing the Messier list I made arrangements with my friendly neighbors to turn off their outdoor lighting when they saw a red light shining thru my bedroom window (sorta like a Bat-signal). So making an effort to become friends with the locals can help too. And obviously, using LPRs and comet filters can be advantageous.

I find that I can usually deal with non-local light pollution. Either you see the object or you don't. There's little ambiguity. But if you have bad local light pollution, there's really no defense, particularly with the new LED lighting. That's my issue where I live now in Hopkins.

Our access to Carver Reserve provides an interesting case study about lighting. Even though the site is 15 miles closer to Minneapolis than ELO, the limiting magnitudes are pretty close. The reason is that ELO is up on a hill and the entire Minneapolis light dome is directly visible. Meanwhile, at Carver Reserve it's pretty secluded with lakes on 3 sides, no local lights and trees blocking a good part of the Minneapolis light dome to the NE. This gives the effect of darkening the sky somewhat, and the dark surroundings help with visual observing... I've viewed 13th magnitude comets from Carver Reserve with my 12" Dob. In December 2018 a few of us viewed very large and diffuse Comet Wirtanen naked eye from Carver Reserve when it was around mag. +4.5.

Suresh

[Thor]

An update. I have been doing some "proof of concept" experiments as I have hauled up more and more equipment to my roof. Last night (under surveillance by patrolling helicopters), I was able to get my mount polar aligned and semi-calibrated (still learning the Losmandy GoTo I recently acquired). Although it was only a faint smudge, I made several exposures of M13 on my DSLR at ISO 3200. I had to lockup the mirror and hold my breath because my flat roof is not much different than a rubber trampoline.

Today I processed the raw files, and composited them in Photoshop. Wondering what I should expect, I encountered the work of Trevor Jones who described photographing M13 from his backyard: https://astrobackyard.com/m13-globular-cluster/. He integrated over two hours of exposure and got a nice portrait. I integrated four 1-second frames and, while not nearly as clean, suggests that it may indeed be possible to do this type of work from my city location.

I'd love to share the comparison images, but don't know how to do that in this forum platform.

[Deane Clark]

Thor, if you use the “Full Editor & Preview” button, that editor will allow you to embed pictures in your posts.

[Thor]

(An attempt to post images).
My quick feasibility test, followed by a shot from a skilled practitioner:
[img][/img]

[Thor]

I was excited by this result. The long exposure by Jones revealed a galaxy smudge (NGC 6207 at lower left) in his image. It might not be visible in mine at this resolution, but I can find it in the full res raw images!

I also know that more/longer exposures will bring the signal above the sensor noise. But that will require getting off the trampoline and anchoring the mount to something structural in my roof.