Can you visit Holt and Miller Observatory (Franklin Institute)? Yes
Guided solar viewing through the 10-inch Zeiss refractor Sat-Sun 12-3 with museum admission; occasional ticketed Night Skies evenings.
Renamed: Franklin Institute rooftop observatory, formerly Joel N. Bloom Observatory, now presented as Holt and Miller Observatory.
A public night at an observatory usually starts at dusk with a short talk, then a line at the eyepiece of the main telescope for the Moon, a planet or a bright cluster, with volunteers' smaller telescopes set up outside. Dress for the night air even in summer: domes are not heated, so the telescope stays at outside temperature. Many nights sell out or cancel for clouds, so check the observatory's site on the day.
Telescopes at Holt and Miller Observatory (Franklin Institute)
10-in Zeiss-Jena Refractor, multiple portable scopes.
How dark the sky is at Holt and Miller Observatory (Franklin Institute)
Holt and Miller Observatory (Franklin Institute) has no Bortle rating in the list yet. The scale below shows what each class looks like.
Sky brightness and class come from the World Atlas of Artificial Night Sky Brightness (Falchi et al. 2016, CC BY-NC 4.0), with natural skyglow added, at the coordinates below. Research telescopes are often sited on mountains above the haze, so the real sky can be darker than the map suggests.
Holt and Miller Observatory (Franklin Institute) among the observatories of Pennsylvania
Green dots are observatories open to the public, blue dots research or private sites, squares dark sky places; select one for its page. See Pennsylvania observatories for the full list.
The coordinates on this page point to zip 19103 (approximate): 39.951°N, 75.174°W.
Map data © OpenStreetMap contributors. Open the larger map · Directions. Mountain observatory roads are often gated after dark; go only on a scheduled public night.
Dark sky places, observatories and clubs near Holt and Miller Observatory (Franklin Institute)
Nearest dark sky places
| Place | Where | Bortle | Distance |
|---|---|---|---|
| Brandywine Creek State Park | Delaware | 6 | 37 km (23 mi) |
| French Creek State Park | Pennsylvania | 4 | 59 km (37 mi) |
| Blackbird State Forest | Delaware | 4 | 80 km (50 mi) |
| Belleplain State Forest | New Jersey | 4 | 83 km (52 mi) |
| Killens Pond State Park | Delaware | 4 | 112 km (70 mi) |
| Delaware Water Gap National Recreation Area | New Jersey | 4 | 126 km (78 mi) |
Other observatories open to the public within 150 km
- Univ. of Pennsylvania ObservatoryPhiladelphia, Pennsylvania, 3 km (2 mi). Teaching observatory on the DRL roof; occasional public observing nights and group visits by arrangement
- Villanova ObservatoryVillanova, Pennsylvania, 18 km (11 mi). Open to the public Mon-Thu 7-9 pm per the Villanova Astronomical Society page; other times by appointment
- Widener University ObservatoryChester, Pennsylvania, 19 km (12 mi). Public viewing sessions through the year
- Mt. Cuba Astronomical ObservatoryWilmington, Delaware, 42 km (26 mi). Monday 8 pm Public Nights (lecture plus viewing, max 28, $10 adults) and select Friday Family Nights; reservations required
- Peyton ObservatoryPrinceton, New Jersey, 65 km (40 mi). Free open houses usually 2nd or 3rd Tuesday monthly at 8:30 pm (Thursday backup), no registration
- Harold E. Taylor ObservatoryGalloway, New Jersey, 73 km (46 mi). Free public viewing nights Sep-early May on select Thursdays/Fridays, 8-10 pm; reservation required (5-minute slots, up to 4 people)
Astronomy clubs within 150 km
- Rittenhouse Astronomical SocietyHaverford, Pennsylvania, 13 km (8 mi). Meets Monthly public speaker meeting, on Zoom (normally in a planetarium)
- Villanova Astronomical SocietyVillanova, Pennsylvania, 18 km (11 mi)
- Delaware Valley Amateur AstronomersBlue Bell, Pennsylvania, 20 km (12 mi). Meets Monthly, usually Friday evening
- Bucks-Mont Astronomical AssociationChalfont, Pennsylvania, 23 km (14 mi). Meets 1st Wednesday monthly (no Aug), 7:30-9 pm
- Chester County Astronomical SocietyWest Chester, Pennsylvania, 36 km (22 mi). Meets 2nd Tuesday monthly (Jan-May, Sep-Nov)
Star parties near Holt and Miller Observatory (Franklin Institute)
| Star party | Near | Distance | Usual timing |
|---|---|---|---|
| Black Forest Star Party | Coudersport, Pennsylvania | 293 km (182 mi) | September |
| Cherry Springs Star Party | Coudersport, Pennsylvania | 293 km (182 mi) | June, near new moon |
| Shenandoah Night Sky Festival | Luray, Virginia | 322 km (200 mi) | Late summer |
| Almost Heaven Star Party | Riverton, West Virginia | 400 km (248 mi) | New-moon weekend in August |
Planning a trip? Astrotourism in Pennsylvania puts the dark sky places, observatories, clubs, star parties, planetariums and science centers of the state on one map, with the best night out worked out.
Holt and Miller Observatory (Franklin Institute) record
Every value in the observatories dataset for Holt and Miller Observatory (Franklin Institute)
| ID | 51 |
|---|---|
| Name | Holt and Miller Observatory (Franklin Institute) |
| Address | The Franklin Institute, 222 N 20th St |
| City | Philadelphia |
| State | PA |
| Zip | 19103 |
| Country | USA |
| Web | https://fi.edu/en/exhibits-and-experiences/holt-miller-observatory |
| Public | y |
| Telescope | 10-in Zeiss-Jena Refractor, multiple portable scopes |
| Lat | 39.95130 |
| Lon | -75.17410 |
| LatLonSpot | zip 19103 (approximate) |
| Status | Renamed |
| StatusNote | Franklin Institute rooftop observatory, formerly Joel N. Bloom Observatory, now presented as Holt and Miller Observatory |
| PublicNote | Guided solar viewing through the 10-inch Zeiss refractor Sat-Sun 12-3 with museum admission; occasional ticketed Night Skies evenings |
| Sources | https://fi.edu/en/exhibits-and-experiences/holt-miller-observatory; https://oa-the-franklin-institute.ticketleap.com/night-skies-in-the-observatory/details |
From the site's observatories dataset (observatories_q426). Distances are computed from the coordinates.