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scope. As it turned out, I could. There are also two observa-

tions from October 2019 using my own 8-inch f/4 Dob.

One of the most valuable things I’ve learned from this

observing project is that getting satisfying observations of

Hubble’s Variable Nebula doesn’t require a huge telescope and

freezing all night under the winter sky at a remote dark-sky

site. Cold winter nights can certainly present a persuasive

argument to stay inside, but NGC 2261 is one of the best

reasons to get out there and observe anyway.

How Long?

After looking at an online animation of images taken over

several months (see https://is.gd/HVNanimation), I had a

hunch I’d be able to see changes over the course of a few

nights. Although that turned out to be true, the shortest

timescale during which I saw defi nite variations was only

24 hours. That was both unexpected and exciting, because I

could see at a glance that the nebula had changed its appear-

ance each time I observed it on consecutive nights. Observa-

S Mon

The Cone

Nebula

HD 47888

Hubble’s

Variable

Nebula

~1°× 1¼ °

The

Christmas

Tree

Cluster

tIN NORTHERN MONOCEROS Tiny NGC 2261 is below and right of the

Cone Nebula and NGC 2264, the Christmas Tree Cluster — the star S Mon

is the bright star at the base of the upside-down tree. By the way, the

Cone Nebula is an extremely diffi cult visual target — have you snagged it?

pZOOMING IN You don’t need a monster of a scope to spot Hubble’s

Variable Nebula — its small apparent size and relatively bright magnitude

yield a high surface brightness. Use the HD stars and their magnitudes (in

parentheses) to estimate the brightness of R Mon. This image is 30′× 30 ′.

POSS-II / STSCI / CALTECH / PALOMAR OBSERVATORY (2)

R Mon

HD 261263 (10.3)

HD 261389 (10.5)

HD 261231 (9.7)

HD 261447 (10.3)

HD 261661 (9.1)

HD 261416 (9.3)

December 6, 2018

28-inch f/4 at 408×

January 1, 2019

28-inch f/4 at 408×

January 14, 2019

28-inch f/4 at 408×

January 30, 2019

8-inch f/3.3 at 164×